Article

Black-browed albatross numbers in Chile increase in response to reduced mortality in fisheries

January 2014
Biological Conservation 169:319-333

DOI:10.1016/j.biocon.2013.12.002

Authors:

Graham Robertson

Retired

Carlos A. Moreno

Universidad Austral de Chile

Javier A Arata

Steven G. Candy

SCandy Statistical Modelling Pty Ltd

Show all 10 authorsHide

Primer estudio sistemático de la colonia reproductiva de albatros de ceja negra Thalassarche melanophris (Temminck, 1828) en el Seno Almirantazgo, Tierra del Fuego (Chile)

Article

Full-text available

Dec 2021

Primer estudio sistemático de la colonia reproductiva de albatros de ceja negra Thalassarche melanophris (Temminck, 1828) en el Seno Almirantazgo, Tierra del Fuego (Chile)

Colaboración científica con la Armada de Chile en estudios ornitológicos a largo plazo en el archipiélago Diego Ramírez: Primer monitoreo del ciclo anual del ensamble de aves en la isla Gonzalo

Article

Full-text available

Dec 2020

Biocultural conservation increasingly requires transdisciplinary collaborations, which includes different disciplines, institutions and actors. The collaboration between scientists and the Chilean Navy has been an effective way to address this requirement. This inter-institutional collaboration between the Navy and the Sub-Antarctic Biocultural Conservation Program (University of Magallanes, Institute of Ecology and Biodiversity and Omora Foundation in Chile, and the University of North Texas in the US) enabled us to initiate in 2016 long term ornithological studies in the Diego Ramírez Archipelago, which includes the southernmost islands of the American continent. Until now, its avifauna has been studied exclusively during summer seasons, despite the fact that birds are one of the most sensitive and fastest responding groups of animals to climate change; modifying their periods of migration, residence and nesting, their population sizes, and their latitudinal distribution areas. In addition, subpolar regions are especially sensitive to climate change and studies in the Cape Horn Biosphere Reserve, adjacent to the Diego Ramírez Archipelago, suggest that some species could be expanding their latitudinal distribution spheres and changing their migration dates. The objective of this work is to initiate a systematic monitoring of the species composition and the nesting, migration and/or residence dates of the Diego Ramírez Archipelago birdlife at the southern tip of the Magallanes sub-Antarctic ecoregion. In this study we present an update of the avifauna records for the Gonzalo Island, Diego Ramírez Archipelago, including the first fall and winter records, and sightings at other times of year. In three expeditions, during the austral reproductive season (summer, November 29-December 1, 2016), winter (July 20-22, 2017) and fall (March 28-April 1, 2018), birds were monitored using mist-nets and creating species lists from field observations. For the observations of birds throughout the year, we used the photographic records made by José Mella (coauthor) and José Mejía (Navy petty officers at Gonzalo Island Lighthouse, years 2014-2018), and new photographic records were initiated with trained personnel of the Navy of Chile in the lighthouse of Gonzalo Island. In total, we detected 33 species belonging to 16 families. Ten of these species represent new records for the archipelago: Neotropic cormorant (Phalacrocorax brasilianus Gmelin, 1789), Western cattle egret (Bubulcus ibis (Linnaeus, 1758)), Peregrine falcon (Falco peregrinus Tunstall, 1771), Austral negrito (Lessonia rufa Gmelin, 1789), Austral thrush (Turdus falcklandii Quoy & Gaimard, 1824), Rufous-collared sparrow (Zonotrichia capensis Müller, 1776), Black-chinned siskin (Spinus barbatus Molina, 1782), Blue-and-White Swallow (Pygochelidon cyanoleuca patagonica d’Orbigny & Lafresnaye, 1837), Black-bellied storm petrel (Fregetta tropica Gould, 1844), and y Cape petrel (Daption capense capense Linnaeus, 1758). Some of these new records could be associated with global warming and a recent expansion of the latitudinal distribution areas and/or the residence periods of these birds. Among the 33 species, 26 were recorded in spring-summer, 22 in fall, and 14 in winter. However, nine were sighted only occasionally and it will be necessary in the future to determine whether they are resident or migratory species that are seldom observed, or occasional visitors. Regarding conservation status, according to the IUCN Red List of Threatened Species, the avifauna of the Diego Ramírez Archipelago includes an endangered species (Grey-headed albatross, Thalassarche chrysostoma Forster, 1785), three vulnerable species and four almost threatened. Monitoring on these islands provides a baseline to evaluate the status of bird populations under the threats of global change, among which the threat of invasive species is highlighted. It is critical to prevent the arrival of exotic invasive species that are present in other subantarctic islands, such as rats (Rattus spp.), mice (Mus musculus Linnaeus, 1758), cats (Felis catus Linnaeus, 1758), and American mink (Neovison vison Schreber, 1777), which are present in the Cape Horn Biosphere Reserve, located less than 100 km North of the Diego Ramírez Archipelago. The collaborative work with the Chilean Navy has been crucial to start these long-term ornithological studies, associated with the new Long-Term Ecological Studies Site Gonzalo Island-LTER that forms part of the Chilean Long-Term Socio-Ecological Studies Network (LTSER-Chile), and the International Long-Term Ecological Studies Network (ILTER). A main goal will be to combine avifauna monitoring with detection of potential invasive species.

Incidental seabird mortality and discarded catches from trawling off far southern Chile (39–57°S)

Article

Jul 2019

In world fisheries, incidental non target species mortality have turned in a permanent debate issue. Although many studies have dealt with these interactions from a descriptive overview, there is little information based on fishing operations data. One of the most important species that have awakened scientific concern are seabird, being southern Chile one of the areas with the highest levels in this kind of interactions. In order to improve our understanding on these relationships, we analyze records of fishing hauls of industrial trawlers off the coast of Chile between 39 and 57°S. The results showed that incidental seabird mortality appears to be affected mainly by the collisions with net monitoring systems (net-sonde cable), the duration of fishing hauls, the year period, and the fishing zones, these last related to the breeding period and areas of albatross colonies. We indirectly address a probable relationship between seabird mortality and fishing discards, and some hypothesis are proposed to explain the results. Finally, we demonstrated that longer fishing hauls are less efficient for fishing, beside to a high seabird mortality. Our findings suggest mitigation actions that would harmonize fishing activity with the ecosystem, in particular, for trawl fishing management and operations off far southern Chile.

Variation in live-capture rates of albatrosses and petrels in fisheries, post-release survival and implications for management

Article

Full-text available

Jul 2020
BIOL CONSERV

Bycatch of seabirds in longline fisheries includes mortalities and live captures (mainly during hauling). Excluding outliers, the latter accounts for 5–70% (mean 40.4%) of all bycaught birds in demersal, and 3–23% (mean 10.7%) in pelagic longline fisheries. The proportion that later die from injuries is unknown, and this cryptic mortality complicates efforts to quantify fisheries impacts. Over a 26-year period at South Georgia, foul-hooking indices - birds with embedded hooks or entangled among tens of thousands checked at the colony - were broadly similar in wandering albatrosses Diomedea exulans and giant petrels Macronectes spp., an order of magnitude lower in black-browed albatrosses Thalassarche melanophris and nil in two other albatross species. This likely reflected differing degrees of overlap with fisheries and interaction with gear during hauling. Indices peaked in the early-mid 2000s, then declined, broadly corresponding with changing fishing practices, including the lagged effect of a seasonal fisheries-closure, introduction of a new fishing system, reduced effort in some demersal fisheries and general improvements in bycatch mitigation. Foul-hooking indices at colonies can therefore reflect relative risk for different species over time, and be a useful adjunct to vessel-based monitoring of live-capture rates. Taking into account age and status when reported, and annual survival probabilities, subsequent survival of live-caught and released wandering albatrosses was around 40% of that expected for the wider population. This has major implications for ecological risk assessments that seek to determine the impacts of fisheries on seabirds, as most do not currently consider deleterious impacts of live capture.

Pelagic longlines and albatross in the southern Indian Ocean: interactions of fleet dynamics, climate change, and albatross

Thesis

Full-text available

Aug 2017

Pam Michael

The greater Southern Ocean is vast, valuable, and vulnerable. Land masses are few and intense atmospheric and oceanographic conditions create a mosaic of logistical challenges for access. The Southern Ocean is home to unique species, including all but three of the world’s albatross species and high value tunas targeted by distant-water pelagic longline fleets from multiple flagstates. Exploitation of tunas has contributed to some stocks being over-fished while indirect exploitation, through incidental bycatch, has severely impacted many albatross colonies. The impacts of climate change will further complicate the current interactions within the Southern Ocean, including those between fish, fishers, and albatross. This thesis predicts the potential future for Southern Ocean tuna, fishers, and albatross, focusing on the Indian Ocean sector of the Southern Ocean, with some analyses in the Atlantic sector as well. The first chapter introduces the Southern Ocean, major tuna fisheries, their interactions with albatross and the potential impacts of climate change. It then describes the approach taken in this thesis. As fishers interact with both fish and albatross, the second chapter quantifies the broad-scale patterns in pelagic longline effort across both the Indian and Atlantic sectors of the Southern Ocean. This assessment reveals a strong seasonal cycle in the magnitude and distribution of effort in both sectors, generally in association with changing target species. This shift in target species is associated with both ecological (species moving to different areas) and management (start of the quota year) conditions. The third chapter develops a novel approach to modeling fleet dynamics for distant water pelagic longline effort for Japanese and Taiwanese fleets. These models project the potential impacts of climate change on the distribution of fishing effort. From a range of effort allocation strategies that consider modelled catch per unit effort (CPUE) of four different tuna species, cost, value, and predicted variability in CPUE in each fished area, the distribution of effort in both fleets was most similar to preferentially allocating effort into areas of low predicted variability. Using environmental parameters projecting climate change in our tuna distribution models, the models forecast an average decrease in CPUE, an increase in the average predicted variability of CPUE, and decrease in effort, related to the fishing strategy identified above; fishing in areas of low predicted variability. The fourth chapter assesses the population dynamics of black-browed albatross (Thalassarche melanophris) breeding on Kerguelen Island, in the central western portion of the study area. This assessment uses an integrated population model structured by sex, age-class, breeding stage, and reproductive history and operates on a monthly, 5˚ × 5˚ temporal and spatial scale. We quantify the bycatch of each super-fleet (fleets grouped by gear-type and reported bycatch rates) and the impact of environmental conditions on the albatross population. These analyses indicate that high bycatch in the 1990s- early 2000’s decreased the population, with bycatch attributed to illegal, unreported and unregulated (IUU) demersal and non-Japanese pelagic longline effort, although the model’s ability to differentiate bycatches between pelagic super-fleets is weak. In line with other studies, warmer SSTs during the incubation period favors higher productivity. In the final research chapter, the models described above (Ch. 3 and 4) are combined to project the synergistic impacts of climate change on albatross and fleet dynamics. Reduced effort by the Taiwanese and Japanese fleets had very little impact on the population, as bycatch by pelagic longline fleets was projected to be virtually absent even with higher levels of effort. The impact of warming SST during the incubation period increased chick survival. However, the associated increase in juvenile and immature albatross in the following years results in a density-dependent decrease in juvenile survival to age five, ultimately reducing the total number of breeding pairs in the population relative to a projection assuming no change in SST. This work presents one of the first examples of research combining fleet dynamics with albatross population dynamics to quantify the potential impacts of climate change. The patterns identified in the broad-scale distribution of fishing effort (Ch. 2) informed the development of the fleet dynamics model (Ch. 3). After a thorough analysis of the drivers of black-browed albatross population dynamics, including the environment and bycatch of multiple fleets (Ch. 4), these projections were combined (Ch. 5).This approach demonstrates the utility of fleet dynamics models and underscores the flexibility of integrated population models when assessing how changes in multiple factors (e.g. environmental parameters, bycatch) can impact a given population in the future. These types of models can assist conservation and fisheries managers make important decisions regarding mitigation of both bycatch and the environmental impacts of climate change.

DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

Article

Full-text available

Aug 2017

Almost all of the world's fisheries overlap spatially and temporally with foraging seabirds, with impacts that range from food supplementation (through scavenging behind vessels), to resource competition and incidental mortality. The nature and extent of interactions between seabirds and fisheries vary, as does the level and efficacy of management and mitigation. Seabird dietary studies provide information on prey diversity and often identify species that are also caught in fisheries, providing evidence of linkages which can be used to improve ecosystem based management of fisheries. However, species identification of fish can be difficult with conventional dietary techniques. The black-browed albatross (Thalassarche melanophris) has a circumpolar distribution and has suffered major population declines due primarily to incidental mortality in fisheries. We use DNA metabarcoding of black-browed albatross scats to investigate their fish prey during the breeding season at six sites across their range, over two seasons. We identify the spatial and temporal diversity of fish in their diets and overlaps with fisheries operating in adjacent waters. Across all sites, 51 fish species from 33 families were identified, with 23 species contributing >10% of the proportion of samples or sequences at any site. There was extensive geographic variation but little inter-annual variability in fish species consumed. Several fish species that are not easily accessible to albatross, but are commercially harvested or by-caught, were detected in the albatross diet during the breeding season. This was particularly evident at the Falkland Islands and Iles Kerguelen where higher fishery catch amounts (or discard amounts where known) corresponded to higher occurrence of these species in diet samples. This study indicates ongoing interactions with fisheries through consumption of fishery discards, increasing the risk of seabird mortality. Breeding success was higher at sites where fisheries discards were detected in the diet, highlighting the need to minimize discarding to reduce impacts on the ecosystem. DNA metabarcoding provides a valuable non-invasive tool for assessing the fish prey of seabirds across broad geographic ranges. This provides an avenue for fishery resource managers to assess compliance of fisheries with discard policies and the level of interaction with scavenging seabirds.

Recent trends in numbers of wandering (Diomedea exulans), black-browed (Thalassarche melanophris) and grey-headed (T. chrysostoma) albatrosses breeding at South Georgia

Article

Full-text available

Jul 2017
POLAR BIOL

South Georgia supports globally important populations of seabirds, including the wandering albatross Diomedea exulans, black-browed albatross Thalassarche melanophris and grey-headed albatross T. chrysostoma, currently classified by the world Conservation Union (IUCN) as vulnerable, near threatened and endangered, respectively. Surveys of these species at South Georgia were conducted during the incubation stage in November 2014 to January 2015, repeating previous surveys conducted in the 2003/2004 season. Numbers of wandering albatrosses breeding annually at South Georgia decreased by 18% (1.8% per year) from 1553 pairs in 2003/2004 to an estimated 1278 pairs in 2014/2015. Over the same period, black-browed and grey-headed albatrosses decreased by 19% (1.9% per year) and 43% (5% per year), respectively. These represent a continuation of negative trends at South Georgia since the 1970s and are in contrast to some populations elsewhere, which have shown signs of recent recovery. Given the importance of South Georgia for these species, the ongoing population declines, and in the case of grey-headed albatrosses, an acceleration of the decline is of major conservation concern. Incidental fisheries mortality (bycatch) is currently considered to be the main threat. Although seabird bycatch has been reduced to negligible levels in the fisheries operating around South Georgia, wider implementation of effective seabird bycatch mitigation measures is required to improve the conservation status of the South Georgia populations of wandering, black-browed and grey-headed albatrosses. In addition, more research is required to investigate the respective roles of bycatch and climate change in driving these population trends.

Continued increase in the number of black-browed albatrosses (Thalassarche melanophris) at Diego Ramírez, Chile

Article

Full-text available

May 2017
POLAR BIOL

Black-browed albatrosses (Thalassarche melanophris) are killed incidentally in commercial fishing operations. Aerial surveys in 2002 and 2011 revealed the number of black-browed albatrosses at the Diego Ramírez and Ildefonso islands, Chile, increased by 52 and 18 %, respectively. The increases were attributed to reduced mortality in the longline fishery for Patagonian toothfish (Dissostichus eleginoides) following fleet conversion to a new gear configuration with much higher average hook sink rates. A new survey in 2014 revealed the number of black-browed albatrosses at Ildefonso was about the same as in 2011, but the number at Diego Ramírez had increased by a further 29 % (8.8 %/year). The number of grey-headed albatrosses (Thalassarche chrysostoma) at Diego Ramírez also increased, by 23 %, in the same time period. In 2014, Ildefonso held an estimated 54,284 breeding pairs of black-browed albatrosses. The populations of black-browed albatrosses at two more northern sites, the Evangelistas and Leonard islets, stood at 4818 and 545 breeding pairs, respectively. The total number of breeding pairs of both albatross species at Diego could not be determined because not all islands in the archipelago were surveyed.

The industrial demersal floated longline system for Austral Hake and Congrio in Chile: initial sink rates and effect of added floats

Conference Paper

Aug 2021

An experiment was conducted to determine the sink rates near the surface of demersal floated longlines (weighted with 8 kg every 50 m) as used in Chile for Austral hake and Congrio. Sections of line without floats attached midway between weights took, on average, 19 sec to reach 2 m depth (0.10 m/s) compared to 80 sec (0.02 m/s) for floated sections, a difference of almost an order of magnitude. Comparative mean distances astern (at 6 knots setting speed) were ~60 m and ~260 m for unfloated and floated gear, respectively. Estimates for the 0-5 m depth range were 39 sec (0.13 m/s) for unfloated sections and 141 sec (0.03 m/s) for floated sections and between ~140 and ~440 m astern with the distance depending on the presence or absence of floats. The differences between gear types were explained mainly by the time taken from water entry to commencement of sinking when gear was held aloft and most available to seabirds. Unfloated sections of the line took ~8 seconds to commence sinking compared to 70-75 sec for floated sections, which 'floated' in the 0-1 m depth range just beneath the surface. The challenge is to implement changes that negate the effect of floats in the first several metres of the water column so the sink profile of gear with floats resembles that of gear without floats.

Disentangling the Influence of Three Major Threats on the Demography of an Albatross Community

Article

Full-text available

Feb 2021

Climate change, fisheries and invasive species represent three pervasive threats to seabirds, globally. Understanding the relative influence and compounding nature of marine and terrestrial threats on the demography of seabird communities is vital for evidence-based conservation. Using 20 years of capture-mark-recapture data from four sympatric species of albatross (black-browed Thalassarche melanophris, gray-headed T. chrysostoma, light-mantled Phoebetria palpebrata and wandering Diomedea exulans) at subantarctic Macquarie Island, we quantified the temporal variability in survival, breeding probability and success. In three species (excluding the wandering albatross because of their small population), we also assessed the influence of fisheries, oceanographic and terrestrial change on these rates. The Southern Annular Mode (SAM) explained 20.87–29.38% of the temporal variability in survival in all three species and 22.72–28.60% in breeding success for black-browed and gray-headed albatross, with positive SAM events related to higher success. The El Niño Southern Oscillation (ENSO) Index explained 21.14–44.04% of the variability in survival, with higher survival rates following La Niña events. For black-browed albatrosses, effort in south-west Atlantic longline fisheries had a negative relationship with survival and explained 22.75–32.21% of the variability. Whereas increased effort in New Zealand trawl fisheries were related to increases in survival, explaining 21.26–28.29 % of variability. The inclusion of terrestrial covariates, reflecting extreme rainfall events and rabbit-driven habitat degradation, explained greater variability in trends breeding probability than oceanographic or fisheries covariates for all three species. These results indicate managing drivers of demographic trends that are most easily controlled, such as fisheries and habitat degradation, will be a viable option for some species (e.g., black-browed albatross) but less effective for others (e.g., light-mantled albatross). Our results illustrate the need to integrate fisheries, oceanographic and terrestrial processes when assessing demographic variability and formulating the appropriate management response.

Plastic debris and seabirds: Updating an old story

Chapter

Jan 2015

The importance of ocean pollution, including pollution from plastics, has been recognized for a long time. However, the current generation and disposal of plastic worldwide has no precedent. Plastic litter accounts for 50-80% of waste items stranded on beaches, floating on the ocean surface and lodged in the seabed. Floating plastic debris is usually ingested by marine animals by mistake, or because it resembles their natural food. This plastic intake by animals such as seabirds can produce entanglement, intoxication, internal wounds, digestive tract blockage and ulcers among other conditions. While these damages are important, further concerns have arisen about plastics sorbing potentially hazardous hydrophobic chemicals. These compounds found in the waters where plastics are, can be plastic additives from other degrading plastics such polychlorinated biphenyls (PCBs) or chemicals from other sources like persistant organic pesticides (POPs), both with the capacity of being sorbed by plastics. However, the importance of the ingestion of plastic-derived chemicals present in the natural prey of seabirds through biomagnification, compared with the amount of these chemicals intake via plastic debris is still being studied. The finding of PCBs and POPs in the ingested plastic pellets and plastic fragments, have led to additional research aimed at assessing the relative potential of plastic as a vector of pollutants transport. The results of these studies are until now contradictory, largely because the role of the dilution and cleaning mechanisms of the studied chemicals are under debate. The impact of plastic debris on individuals is well known although it is not entirely clear how plastic ingestion at the individual level could impact the whole population and how this will impact entire ecosystems. For example, one strategy to mitigate damage caused by ingested plastics is to regurgitate them, so the transference of these plastics to chicks is not uncommon while being fed. As most chicks are unable to regurgitate plastic fragments, these accumulate in their stomachs eventually causing death. At present, the implications of chemicals sorbing on the population size of seabirds is unknown. The effectiveness of using seabirds as monitors has increased considerably in recent years. Sampling the stomach contents of beached birds, birds killed accidentally by fishing activities or by examining regurgitated pellets of predators that feed on seabirds can be useful as well. Nonetheless, there are still questions to answer before we can confidently assess the impact of plastic waste on the environment through seabirds. For example: Is there a linear relationship between pollutants sorbed and the surrounding plastic debris? Or do birds reach a point where they become saturated by these chemicals independently of their plastic ingestion? Throughout this chapter we will evaluate the progress made to answer the open questions about the impact of plastic debris on seabirds and discuss the future of seabirds as a group and their use as monitors of plastic pollution to evaluate the health of ecosystems.

Seabirds and island communities: Biodiversity awareness as a tool for the conservation of insular species

Chapter

Full-text available

Jan 2015

Seabirds can serve as fundamentally important components of biodiversity of insular ecosystems, playing an important role as vectors of marine-derived nutrients, increasing primary production which in turn is transferred through the food web, and influencing the numbers and types of primary and secondary consumers. The status and trends of seabirds can be an excellent indicator of the impacts of human activities on their populations and communities. These impacts include loss of breeding sites through trampling and grazing by introduced domesticated animals; mortality by introduced mammalian predators such as rats, dogs and cats; egg and chick harvest; and interactions with local and regional fisheries. These impacts have occurred on most human-inhabited islands, ranging from the tropics to the sub-polar regions. Until the 1990s, the general state of knowledge about seabirds of oceanic islands in Chile was poor, since virtually no basic ecological information such as population size, breeding biology or the extent of conservation problems had been compiled for many species. Human communities of oceanic and coastal insular systems in Chile currently possess only a small percentage of people who retain local traditional ecological knowledge, as a result of the recent influx of immigrants during the second half of the 20th century and the progressive decline of the ancestral native population. The relationship of recently arrived human communities with the biodiversity of the insular systems has been restricted to the use and exploitation of resources to satisfy basic needs for the human population (e.g. heating, food). Many of these activities have a negative impact on the biodiversity of the island, including seabirds. As a resource, seabirds were usually ignored by island communities because they did not provide any immediate benefit. In the 1990s, initiatives of national and foreign researchers began in different islands of Chile to elucidate basic aspects of the ecology and conservation status of several seabird species. The information generated was shared with the island communities associated with these seabird species in order to increase awareness and build support for conservation actions. This community engagement was undertaken based on the understanding that island communities, especially isolated ones, have particular characteristics that distinguish them from the inhabitants of the continent. These include a strong sense of belonging to the place, a heightened sense of community among residents, a detachment from the nearby continental areas, and a sense of not belonging to the central government that manages the island. Here we document community engagement experiences and results on five significant Chilean seabird islands distributed in a wide latitudinal range: (1) Robinson Crusoe, Santa Clara and Alejandro Selkirk islands (the Juan Fernandez Archipelago) (34° S), inhabited by six species of procellarids (Pink-footed Shearwater Puffinus creatopus, Kermadec Petrel Pterodroma neglecta, De Filippi's Petrel Pterodroma defilippiana, White-bellied Storm-Petrel Fregetta grallaria, Juan Fernandez Petrel Pterodroma externa and Stejneger's Petrel Pterodroma longirostris); (2)Mocha Island (38° S) where the Pink-footed Shearwater Puffinus creatopus breeds; (3) Punihuil Island, Chiloe (42° S) with a mixed-colony of Humboldt (Spheniscus humboldtii) and Magellanic (Spheniscus magellanicus) penguins; (4) Guafo Island, Quellen town (44°S) with the largest colony of Sooty Shearwater Puffinus griseus in the world; and (5) Navarino Island (55°S), Cape Horn Biosphere Reserve, that is inhabited by rich ensembles of seabirds and shorebirds, including cormorants, plovers, sandpipers, steamer-ducks and geese. On all of these islands, islanders have participated in initiatives that support the conservation of resident seabird species, including the cessation of chick and egg harvests, development of special interest tourism around birds, removal of introduced animals and responsible pet ownership, and as a general rule, inclusion of birds as co-inhabitants of the community.

Seabird Conservation in Fisheries: Current State of Knowledge and Conservation Needs for Argentine high-seas Fleets

Chapter

Full-text available

Mar 2015

Interactions between pelagic seabirds (albatrosses and petrels, Procellariiformes) and fisheries occur in all oceans of the globe, virtually in all fisheries, and are dominated by the effect of fishing on birds. Despite the fact that provisioning of fishery discards and offal to birds can be viewed as beneficial, incidental mortality in fisheries is by far the main at-sea threat albatrosses and petrels are facing nowadays, and certainly the main cause of declinations in populations recorded in modern days. This chapter offers an overview of interactions between pelagic seabirds and high-seas Argentine fishing fleets, including longliners, trawlers and jiggers. The first section of this review looks into the nature of interactions between seabirds and fisheries, particularly in the Southwest Atlantic Ocean. The second section seeks to define the fishing effort of the different fleets operating in national waters providing a summary of extant fishery regulations and management measures related to the main target species, the Argentine hake Merluccius hubbsi. The third section explores available information regarding conservation status and use of marine space by seabirds attending and interacting with a number of high-seas fisheries, including bycatch levels and mitigation measures, as well as issues dealing with the implementation and compliance of conservation and management measures. The fourth section provides insight into the use of fishery discards and offal by non-breeding pelagic seabirds attending vessels, taking the Black-browed Albatross Thalassarche melanophris as a case study. Finally, the fifth section reviews the up-to-date scientific, legal, and political actions taken to protect seabirds in Argentine waters, referring to possible steps for implementing an ecosystem approach to national fisheries within the frame of Argentina‘s National Plan of Action – Seabirds.

Síntesis y revisión crítica del uso de bio-registradores para aves marinas en SudaméricaSynthesis and Critical Review of the Use of Bio-loggers for Seabirds in South America

Article

Full-text available

Jan 2025

El desarrollo y utilización de complejos registradores electrónicos de movimiento y comportamiento animal, con múltiples sensores que registran datos a más de 50 Hz, produjo destacados avances en el conocimiento de la ecología de muchas especies de aves marinas. Sin embargo, en Sudamérica, la mayoría de los estudios se enfocan en una primera línea de conocimiento, relacionada casi exclusivamente con el uso del espacio. El mayor grado de desarrollo de este tipo de tecnología y del análisis de los datos derivados, han sido aplicados solo en unas pocas especies y sitios de estudio. Si bien la combinación del uso de sofisticados sensores (i.e., acelerómetros y magnetómetros) y el desarrollo de programas innovadores para el análisis y la visualización de los datos a partir de métricas novedosas han abierto nuevos escenarios de investigación a escala fina de los movimientos y comportamientos, estas herramientas están aún subutilizadas. Este trabajo ofrece una síntesis de la variedad de herramientas tecnológicas, de sus alcances y las métricas disponibles para el estudio de la ecología del movimiento animal. A su vez, presenta una revisión crítica del uso de bio-registradores en aves marinas y reflexiona sobre la necesidad de profundizar en el conocimiento de la ecología de este grupo en la región.

The white-capped albatross: a new breeding record for the Diego Ramírez Islands, Chile

Article

Full-text available

Jun 2024
POLAR BIOL

Albatrosses are renowned for their high philopatry, which has been proposed as a major barrier to their dispersal and hybridization with other albatross species. Except for shy-type albatross species from New Zealand, examples of colonization of new breeding sites and interbreeding with closely related species are rare. During the austral summer of 2022, while conducting land-based monitoring of resident Black-browed (Thalassarche melanophris) and Grey-headed (T. chrysostoma) albatross populations on the Diego Ramírez Islands, Chile (56 S), we documented the first (and southernmost) breeding record of a nesting pair of White-capped Albatross (T. steadi), a species endemic to the Auckland Islands, New Zealand (~ 7000 km away). The species identity was confirmed through molecular analysis. This discovery underscores the importance of Diego Ramírez and its surrounding waters as a hotspot for global albatross conservation.

Foraging habitat suitability of black-browed albatrosses Thalassarche melanophris wintering in the South-west Atlantic Ocean: Acknowledging age class to improve conservation management

Article

Jan 2024

1. Seabirds, particularly albatrosses, are among the most threatened birds as a result of their continuous exposure to anthropic pressures including interaction with commercial fisheries, climate change and pollution. Several studies that have focused on the spatial distribution of foraging seabirds have identified a certain level of segregation between age classes. 2. The black-browed albatross Thalassarche melanophris is the most abundant albatross species in the South-west Atlantic Ocean and the main pelagic seabird interacting with a range of fishing fleets. There is a considerable lack of knowledge about the biology of immature individuals and on habitat suitability of the species during non-breeding season (winter). 3. The aim of this study was to assess the foraging habitat suitability of the blackbrowed albatross in the South-west Atlantic during the austral winter, analysing differences between adults and immatures individuals. 4. Habitat suitability models were based on foraging locations recorded by 15 satellite transmitters deployed on six adults and nine immature individuals between 2011 and 2015. Remotely sensed oceanographic data were used to characterize suitable foraging habitat for the albatrosses. 5. Differences were found in foraging habitat suitability by age class, with adult selecting areas located in deeper waters over the continental shelf break as well as in neritic zones under cooler water temperatures, whereas immature individuals foraged chiefly off coastal waters having more moderate temperatures. 6. Knowing habitat suitability and segregation patterns within-species is key for the conservation of critical marine habitats given that, by only considering one age class, other important habitats would be neglected and not considered in conservation efforts to mitigate threats such as incidental mortality. It is important to include all age classes when studying patterns of associations with threats, such as fishing activity as a proxy of risk of bycatch, and for the development of Marine Protected Areas.

Áreas de importancia para la conservación de aves marinas en el Mar Argentino: el Albatros Ceja Negra (Thalassarche melanophris) como especie clave

Technical Report

Full-text available

Dec 2023

La planificación espacial marina es una herramienta de gestión útil para la conservación de la biodiversidad. Depredadores como las aves marinas pueden utilizarse como indicadores biológicos, tanto para monitorear el estado de los ecosistemas marinos como para identificar y priorizar áreas para la conservación marina. El Albatros Ceja Negra (Thalassarche melanophris) es una de las especies de aves marinas más abundante del Atlántico Sudoccidental y listada como Vulnerable a nivel nacional, siendo las altas tasas de captura incidental en buques pesqueros una de las principales causas de esta categorización. El presente estudio tuvo como objetivo definir áreas prioritarias para la conservación en el Mar argentino, utilizando al Albatros Ceja Negra como estudio de caso y especie clave. Se realizaron análisis de priorización espacial utilizando información de idoneidad de hábitat de la especie, así como variables antrópicas relacionadas a la actividad pesquera (esfuerzo pesquero y áreas de veda) como limitantes o forzantes en la selección de áreas. Las áreas prioritarias de base (sin considerar la actividad pesquera) identificadas para la conservación de la especie se ubicaron sobre la isobata de 50mdesde el norte de la Península Valdés hasta Mar del Plata, y otras en la desembocadura del Río de la Plata, sobre la isobata de 50m en la Plataforma Bonaerense y una en la zona externa de El Rincón, dependiendo de los años utilizados para el análisis. El análisis de áreas prioritarias incluyendo capas de actividad pesquera permitió la identificación de áreas prioritarias para la conservación dentro de las zonas de veda ya establecidas. La información presentada es útil como insumo para el desarrollo y gestión de Áreas Marinas Protegidas y Otras Medidas Efectivas de Conservación Basadas en Áreas e inclusive el ordenamiento de actividades antrópicas en el Mar Argentino. Citar como: Paz J A, Copello S, Seco Pon J P, Favero M (2023) Áreas de importancia para la conservación de aves marinas en el Mar Argentino: el Albatros Ceja Negra (Thalassarche melanophris) como especie clave. Informes científico-técnicos del Instituto de Investigaciones Marinas y Costeras N°22 (UNMdP-CONICET). 20pp. ISSN 2796-9088 https://www.iimyc.gob.ar/iimyc/wp-content/uploads/2023/12/Informe22.pdf

Habitat suitability under future climate scenarios in black-browed albatross (Thalassarche melanophris) in Southern South America and Antarctica

Article

Full-text available

May 2023
POLAR BIOL

The Black-browed Albatross (BBA), Thalassarche melanophris, is one of the most abundant and widespread pelagic seabirds in the southern hemisphere, considered an indicator species of climate change in Antarctica. In addition to the known negative interactions with fisheries, other threats may act indirectly on this species whose effects have not yet been evaluated, such as increased sea surface temperature due to climate change. Under the assumption that carbon emissions modify the distribution of BBA, we modeled the environmental suitability and inferred BBA distribution under future climate scenarios for 2050 and 2100. We used 23 years of observation data (1991–2020) from research vessels in the Southwest Atlantic Ocean and Antarctica to estimate habitat suitability and predict change in suitability for the two future time ranges (2040–2050 and 2090–2100) under four representative concentration pathway scenarios: optimistic, intermediate pessimistic. Our projections predict a reduction in the total habitat suitability for BBA by 8% and 31.4% by 2050 and 2100, respectively, in the worst-case scenario compared to the present. Our study enhances understanding of the factors driving distribution dynamics for the species and aid in the development of conservation areas under future global change scenarios.

Estrategia Nacional de Conservación de Aves 2021-2030

Book

Full-text available

Sep 2022

El desarrollo no sustentable ha llevado a la pérdida y degradación de una gran cantidad de ecosistemas naturales en Chile, produciendo un impacto negativo sobre su biodiversidad. A pesar de no ser un país megadiverso en su avifauna (528 especies), Chile sí forma parte importante de ecosistemas que poseen un alto grado de endemismo en estas especies y posee hábitats mundialmente reconocidos para la conservación de las aves. Las aves juegan roles fundamentales tanto en procesos ecosistémicos como en el bienestar humano. Por ejemplo, dos tercios de la flora leñosa del centro-sur de Chile hasta Cabo de Hornos es dispersada por aves. Flora y vegetación que aporta en la infiltración de aguas lluvias al suelo, en el control de la erosión y, entre otras cosas, es fuente de una gran cantidad de productos forestales no madereros por comunidades locales. En ambientes costeros, las aves que nidifican en colonias tienen un rol muy importante en el ciclo de nutrientes (ej. Nitrógeno y Fósforo) enriqueciendo en biodiversidad los ecosistemas que habitan. Además, las aves marinas nutren el conocimiento local de pescadores artesanales, informando la presencia de peces objetivo de la pesca. Las aves también pueden ser indicadoras de biodiversidad y/o de la salud de diversos ecosistemas (especies centinelas), lo que puede no sólo ayudar a monitorear estos complejos sistemas naturales, sino también detectar tempranamente amenazas que estén afectando ecosistemas naturales, orientando medidas de manejo y conservación. Las aves y sus hábitats se ven desafiados por un gran número de amenazas en el país, desde aquellas transversales (ej. cambio climático y especies exóticas invasoras) hasta las particulares asociadas a un grupo de aves y/o ecosistema (ej. captura incidental). Lo anterior afecta no sólo la biodiversidad de aves y sus roles ecológicos, sino también, el bienestar humano. De esta manera, se resalta la importancia de establecer una planificación estratégica para la conservación de aves en Chile. Para abordar las amenazas a las aves y sus hábitats, en Chile, se definieron ocho líneas de acción, cada una con un conjunto de acciones asociadas: (1) fomentar la investigación y monitoreo de aves, (2) crear y fortalecer alianzas para la conservación, (3) fortalecer políticas públicas, (4) promover el cumplimiento de la normativa, (5) incentivar e innovar en prácticas sustentables del sector productivo, (6) atraer recursos para la implementación de acciones, (7) elaborar instrumentos de gestión en conservación (8) empoderar y vincular a la comunidad. Esta Estrategia enmarca la acción nacional en conservación de aves y sus hábitats, así como el proceso de elaboración facilita la colaboración y trabajo conjunto para fortalecer el desarrollo sustentable de presentes y futuras generaciones.

Assessing the potential for resource competition between the Kerguelen Plateau fisheries and southern elephant seals

Article

Full-text available

Nov 2022

Indirect ecological interactions such as competition for resources between fisheries and marine predators have often been proposed but can be difficult to demonstrate empirically. The Kerguelen Plateau in the Southern Indian Ocean supports fisheries for both Patagonian toothfish and mackerel icefish and is also an important foraging ground for several avian and mammalian predators, including the southern elephant seal. We quantified the spatio-temporal use of the plateau by southern elephant seals and found that males and females spent 30% of their time on the plateau within the commonly used fishing grounds, indicating the possibility of competition for resources there. We then contrasted the seals’ use of two habitat types, the benthos (where interactions with the long-line fisheries are most likely) and the epi-pelagic zone. The likelihood of feeding on the benthos declined as ocean depth increased and was also less likely at night. Males were also more likely to feed on the benthos than females. The sub-adult male seals consumed an estimated 6,814 – 14,848 tons of high energy content prey (including toothfish) and females 7,085 – 18,037 tons from the plateau during the post-molt winter months. For males this represented 79.6 - 173.4% of the mean annual catch by the Kerguelen fishery compared to 82.8 - 210.7% for adult females. When considering the seals consumption of fish from the benthos within the fishing grounds these estimates decreased to 3.6 - 15.1% of the fishery’s total annual catch for females and 7.8 - 19.1% for males. While this further indicates the possibility of indirect ecological interactions (with the fishery taking more fish than the seals), the lack of detailed diet information for the seals precludes us from establishing the degree or nature of the possible interactions because the importance of toothfish and icefish in the diet of the seals is unknown. However, the unique life history and highly polygynous nature of this species, and the lack of evidence of a measurable effect on either the seal’s population growth rates or the catch per unit of the fishery, suggest that any indirect ecological interactions are not of sufficient magnitude to affect either the seal population or the fishery.

Spatial assessment of albatrosses, commercial fisheries, and bycatch incidents on Canada’s Pacific coast

Article

Full-text available

Aug 2021

Fisheries bycatch mortality poses a primary threat to the majority of the world’s 22 albatross species, 15 of which are at risk of extinction. Although quantitative estimates of albatross bycatch are often unavailable due to a relative or total absence of monitoring, spatial overlap between fisheries and albatrosses is often used to estimate the extent of interaction, a proxy for exposure to bycatch, and to inform avoidance and mitigation actions. Using comprehensive records of commercial demersal longline and trap fishing and survey information for albatrosses (black-footed albatross Phoebastria nigripes, Laysan albatross P. immutabilis, short-tailed albatross P. albatrus), the extent of spatial potential interaction was estimated in Canada’s Pacific coast waters and examined across breeding and non-breeding seasons. The distributions of albatrosses and longline and trap fisheries were found to substantially overlap, with potential interaction hotspots concentrated along the continental shelf break. Trap fisheries reported 1 albatross by - catch incident, suggesting that these fisheries are responsible for negligible albatross mortalities. In contrast, >80% of recorded albatross bycatch incidents occurred within 10 km of longline fisheries−albatross hotspot locations, providing evidence that longline−albatross potential interaction hotspots represent actual areas of elevated bycatch mortality risk. Indicative of potential conservation concern, 60% of short-tailed albatross sightings occurred within 10 km, and 93% within 30 km, of longline−albatross potential interaction hotspots. By contributing knowledge regarding albatross−fisheries interactions, in addition to undertaking the first evaluation of albatross−fisheries hotspots with recorded bycatch incidents on Canada’s Pacific coast, this study represents a step towards enhancing albatross conservation through bycatch avoidance and mitigation.

Mitigating the impact of longline fisheries on seabirds: Lessons learned from the South Georgia Patagonian toothfish fishery (CCAMLR Subarea 48.3)

Article

Sep 2021
MAR POLICY

Seabird mortality in fisheries is a global problem and a major driver of the continued decline of many seabird populations. Unless appropriate mitigation is in place, longline fishing can cause high levels of seabird mortality. Here we describe the development and implementation of seabird mitigation measures in the Patagonian toothfish Dissostichus eleginoides fishery around the sub-Antarctic islands of South Georgia (CCAMLR Subarea 48.3), since the fishery began in the late 1980s. The initial high bycatch mortality (>5000 birds / 0.59 birds per 1000 hooks in 1996) has been reduced to negligible levels (<0.01 per 1000 hooks) through implementation of a suite of mitigation measures and a high level of compliance. The principal species killed in the fishery were black-browed albatross and white-chinned petrels, with most of the mortality occurring in April and early May. Whilst the synchronous introduction of much of the mitigation makes it is difficult to confirm which measures have been most effective, there is compelling evidence that the restriction of the fishery to the austral winter was a major factor. Night-setting and line-weighting measures have also been important in reducing mortality and the 100% observer coverage in the fishery has encouraged high levels of compliance. We also consider how different measures may be effective for different species and how novel measures, such as the use of marked hooks, have helped encourage compliance. The mitigation measures developed in the South Georgia fishery have subsequently been adopted in other CCAMLR fisheries and have helped guide global best practice in addressing seabird bycatch.

Factors (type, colour, density, and shape) determining the removal of marine plastic debris by seabirds from the South Pacific Ocean: Is there a pattern?

Article

Full-text available

Oct 2020
AQUAT CONSERV

1. While floating near the sea surface plastic debris interacts with a number of external factors, including many different organisms. Seabirds have the most extensive documented history of interactions with plastics, through ingestion, entanglement, and nest construction. 2. In the present study, eight seabird species from the South Pacific Ocean were used as a proxy to determine potential patterns of removal of marine plastic debris, and three hypotheses were tested in relation to their feeding habits and nesting areas. 3. Plastics from abiotic compartments (Chilean continental coast, South Pacific Gyre, and Rapa Nui beaches) and biotic compartments (surface‐feeding seabirds, diving seabirds, and nesting areas) were compared, according to their type, colour, shape, and density. 4. Continental beaches had a relatively wide range of colours and shapes, with many non‐buoyant plastics. Samples from the South Pacific Gyre (SPG) and Rapa Nui (Easter Island) beaches comprised mainly hard, rounded, buoyant, and white/grey plastics. 5. These results indicate that the composition of floating plastics from terrestrial sources changes during transport with oceanic currents, reducing the proportion of prey‐like plastics present in the subtropical gyres. 6. The stomach contents of surface‐feeding and diving seabirds were dominated by hard, white/grey, and round plastic items, similar to plastics from the SPG, suggesting non‐selective (accidental or secondary) ingestion. 7. Nesting areas had a more variable composition of brightly coloured plastics, suggesting a pattern of selective removal of plastics by seabirds, probably from oceanic sources. 8. The present study reveals extensive interactions of seabirds with plastics on a broader scale, which is highly relevant given that the impacts of plastics on seabirds are increasing worldwide, compromising their efficient conservation.

Changes in positive associations among vertebrate predators at South Georgia during winter

Article

Full-text available

Oct 2020
POLAR BIOL

We studied positive associations among seabirds and marine mammals at South Georgia on research cruises during the Austral winters of 1985, 1991 and 1993 and found statistically significant differences. We collected data on abundance and distribution, providing a critical reference for sub-Antarctic conservation in anticipation of future environmental changes. We found significant changes in the abundance of 29% of species surveyed and a consequent change in species diversity. We postulate that the resulting altered community composition may have previously unanticipated population effects on the component species, due to changes in positive interactions among species which use each other as cues to the presence of prey. We found a near threefold reduction in spatial overlap among vertebrate predators, associated with warming sea temperatures. As the strength and opportunity for positive associations decreases in the future, feeding success may be negatively impacted. In this way, environmental changes may disproportionately impact predator abundances and such changes are likely already underway, as Southern Ocean temperatures have increased substantially since our surveys. Of course the changes we describe are not solely due to changing sea temperature or any other single cause—many factors are important and we do not claim to have removed these from consideration. Rather, we report previously undocumented changes in positive associations among species, and argue these changes may continue into the future, given near-certain continued increases in climate-related changes.

Future resilience scaled by surveillance: high sensitivity of albatross to regional illegal, unreported and unregulated fishing effort

Conference Paper

Full-text available

Jun 2019

For Kerguelen black-browed albatross (Thalassarche melanophris), warmer sea-surface temperatures (SST) near the colony during incubation have historically promoted chick survival, implying that future increased temperatures would support population viability. However, a historical population decline was driven by by-catch of albatross from the illegal, unreported and unregulated (IUU) demersal longline fleet. The virtual removal of this fleet from the region allowed this population to rebound, yet these albatross are susceptible to by-catch in many fleets and future fishing behaviour is uncertain. Albatross demographics were projected assuming forecast changes in SST and five future fishing effort scenarios. These scenarios indicate a high sensitivity to shelf/slope versus pelagic effort. Specifically, scenarios altering trawl and legal demersal effort estimated slight changes in bycatch while a scenario allowing the re-emergence of the IUU demersal longline effort produced high by-catch estimates and a decline in the number of breeding pairs. Negligible by-catch occurred in pelagic fleets across scenarios. The sensitivity of this population relates to intense use of these habitats during the breeding period, where IUU effort was historically greatest, and diffuse overlap with pelagic effort in non-breeding periods. These findings underscore the importance of continued surveillance and management of by-catch on the plateau region. Résilience future à l'échelle de la surveillance : forte sensibilité des albatros à l'effort régional de pêche illicite, non déclarée et non réglementée Résumé Pour les albatros à sourcils noirs de Kerguelen (Thalassarche melanophris), des températures de surface de la mer (SST) plus élevées près de la colonie pendant l'incubation ont toujours favorisé la survie des poussins, ce qui implique qu'une hausse des températures à l'avenir serait favorable à la viabilité de la population. Cependant, par le passé, la capture accidentelle d'albatros par la flottille de pêche illicite, non déclarée et non réglementée (INN) à la palangre démersale a entraîné un déclin de la population. La disparition quasi-totale de cette flottille dans la région a permis à cette population de rebondir, pourtant de nombreuses autres flottilles posent des risques de capture accidentelle pour les albatros et les futures pratiques de pêche sont imprévisibles. Une Second Kerguelen Plateau Symposium: marine ecosystem and fisheries: 341-353

Diving Behavior of Pink-footed Shearwaters Ardenna creatopus rearing chicks on Isla Mocha, Chile

Article

Full-text available

Dec 2018

Recent information reporting Pink-footed Shearwater Ardenna creatopus mortality from fisheries bycatch throughout its range has encouraged fisheries managers in Chile to evaluate and consider shearwater foraging behaviors to better evaluate risk. In response, we tracked six chickrearing adult Pink-footed Shearwaters from Isla Mocha, off south-central Chile, from 19 to 28 March 2015 using global positioning sensors and time-depth recorders. We recorded seven complete trips averaging 4.2 ± 2.5 d (mean ± SD). Chick-provisioning adults foraged within 334 km (i.e., 175 ± 100 km) of Isla Mocha. Dives (n = 515) occurred throughout the measured foraging range but most frequently occurred within 5–30 km from the mainland coast, in continental shelf waters north of Valdivia. Other regions with diving behavior were within ~20 km of Isla Mocha, and from Lebu to north of Talcahuano. Based on movement behavior analysis, adults spent most of their time at sea “resting/ foraging” (62% ± 6%), with the remainder spent “searching” (16% ± 4%) and “transiting” (20% ± 5%). The proportions of total number of dives associated with these three behaviors were similar. On average, dives were relatively shallow (1.6 ± 1.2 m, maximum depth = 10.1 m) and brief (4.7 ± 4.8 s, maximum duration = 25.7 s). Dives occurred during the day, at night, and at twilight, with most activity occurring at twilight and during the day. Although based on a small sample size, our results may be useful for informing modifications to fishing gear or fisheries policy to reduce the likelihood of bycatch and thus meet Chilean conservation goals for Pink-footed Shearwaters.

In Harm's Way

Chapter

Sep 2018

A large and growing variety of anthropogenic (i.e., human-related) activities threaten birds from the most common to the most critically endangered. Unlike natural threats, such as depredation by native predators and death from storms, the vast majority of anthropogenic mortality factors for birds are recent, emerging since the nineteenth century or more recently. Many bird species are affected by several anthropogenic threats. For example, many Neotropical migrant songbirds face habitat loss on both breeding and wintering grounds, as well as along migratory pathways (i.e., stopover habitat), and they can also die by colliding with many types of man-made structures. In this chapter, we refer to mortality as the general phenomenon or overall amount of bird death from one or more causes, mortality rate as the number of deaths in an area or time period, and fatality as individual occurrences of bird death. In this chapter, we focus on purposeful and incidental direct mortality sources. Major indirect threats are covered elsewhere, including climate change (chapter 24) and habitat loss (chapter 25). Space constraints prevent us from exhaustively covering every direct mortality source. We therefore focus on sources that have received substantial research or are increasingly relevant because of substantial public or conservation attention. The relatively nascent state of the field means that most information about anthropogenic mortality is descriptive, and there is tremendous opportunity for future research to test mortality mechanisms and effects using a hypothetico-deductive approach. Finally, interpreting the overall magnitude of impact for each mortality source and comparing different mortality sources would ideally include consideration of the total number of birds. Yet there are no such scientifically derived estimates for North America, and devising such an estimate is beyond the scope of this chapter. Nonetheless, to provide rough context for the severity of the mortality sources we describe, it is worth considering an often-cited (albeit speculative) estimate of 10–20 billion total birds in North America (USFWS 2002).

Marine biodiversity at the end of the world: Cape Horn and Diego Ramírez islands

Article

Full-text available

Jan 2018
PLOS ONE

The vast and complex coast of the Magellan Region of extreme southern Chile possesses a diversity of habitats including fjords, deep channels, and extensive kelp forests, with a unique mix of temperate and sub-Antarctic species. The Cape Horn and Diego Ramírez archipelagos are the most southerly locations in the Americas, with the southernmost kelp forests, and some of the least explored places on earth. The giant kelp Macrocystis pyrifera plays a key role in structuring the ecological communities of the entire region, with the large brown seaweed Lessonia spp. forming dense understories. Kelp densities were highest around Cape Horn, followed by Diego Ramírez, and lowest within the fjord region of Francisco Coloane Marine Park (mean canopy densities of 2.51 kg m⁻², 2.29 kg m⁻², and 2.14 kg m⁻², respectively). There were clear differences in marine communities among these sub-regions, with the lowest diversity in the fjords. We observed 18 species of nearshore fishes, with average species richness nearly 50% higher at Diego Ramírez compared with Cape Horn and Francisco Coloane. The number of individual fishes was nearly 10 times higher at Diego Ramírez and 4 times higher at Cape Horn compared with the fjords. Dropcam surveys of mesophotic depths (53–105 m) identified 30 taxa from 25 families, 15 classes, and 7 phyla. While much of these deeper habitats consisted of soft sediment and cobble, in rocky habitats, echinoderms, mollusks, bryozoans, and sponges were common. The southern hagfish (Myxine australis) was the most frequently encountered of the deep-sea fishes (50% of deployments), and while the Fueguian sprat (Sprattus fuegensis) was the most abundant fish species, its distribution was patchy. The Cape Horn and Diego Ramírez archipelagos represent some of the last intact sub-Antarctic ecosystems remaining and a recently declared large protected area will help ensure the health of this unique region.

Colección Biológica del Museo Antropológico Martin Gusinde: Su relevancia para la historia natural de los canales subantárticos del Cabo de Hornos

Article

Full-text available

Dec 2017

Como testimonio de la historia natural de un territorio, las colecciones biológicas representan un patrimonio de gran valor ecológico, cultural, histórico y científico. La región de canales y fiordos subantárticos de Magallanes presenta alto endemismo, condición especialmen-te manifiesta en taxones como las aves y los moluscos. Si bien la conservación de especímenes representativos de la biodiversidad de esta zona ha estado concentrada en museos nacionales e internacionales, la Colección Biológica que alberga el Museo Antropológico Martin Gusinde (MAMG) en Puerto Williams aparece como un valioso reservorio local del legado genético, eco-lógico y cultural de los ecosistemas australes de Sudamérica. Con el fin de contribuir a su puesta en valor, realizamos un catastro de las aves y moluscos que reúne, describiendo su importancia ecológica y cultural con énfasis en el vínculo de dichas especies con la historia ancestral y contemporánea del pueblo yagán, y proponiendo algunas aplicaciones.

Seabird Task Force: 2014 - 2017. Technical report.

Technical Report

Full-text available

Sep 2017

The accidental capture of seabirds and other marine animals in fishing gear is referred to as ‘bycatch’. Globally, bycatch is known to be one of the most significant threats to seabirds (Croxall et al., 2012). An estimated 700,000 birds are killed globally each year between the long-line and gillnet fisheries (Žydelis et al., 2013; Anderson et al., 2011). Over the last decades, global conservation work has focused in the southern hemisphere, where albatross bycatch from pelagic longlines and trawlers has decimated populations. Through the pioneering work of groups such as BirdLife’s Albatross Task Force (ATF) in South America and southern Africa, solutions to bycatch in fishing gears have been developed and tested alongside fishermen. This collaborative approach brings huge benefits to both conservationists and the fish-ing sector. Through access to fishing boats and discussions with fishing crew, the expert teams are able to understand the fishing gear and practices and the circumstances behind bycatch events. This information combined with fishermen input is then used to tailor mitigation solutions to individual vessels and fleets. Dramatic reductions in bycatch have been demonstrated using this approach for example Albatross bycatch in South Africa’s demersal trawl fishery was reduced by 95% through the use of bird scaring lines (Maree et al., 2014). Much less work has been carried out in Europe on this topic, despite this region’s significant fishing fleets and seabird populations. A persistent lack of data has not been able to mask that bycatch is a significant conservation issue, however, with an estimated 200,000 birds killed each year, in gillnets and longlines across the region (Žydelis et al., 2013; Anderson et l.,2011; BirdLife International, unpublished). There has therefore been an urgent need to establish an equivalent to the Albatross Task Force. The Seabird Task Force is the first such initiative in this region, and was established in 2014 thanks to the generous support of Fondation Segré. This first project of the Seabird Task Force (STF), saw the creation of a bycatch expert group within Lithuania and Spain focused on two different fishing gears. These countries were chosen for a number of reasons. The Baltic Sea is a hotspot for gillnet bycatch, and previous data indicated that bycatch of threatened seaduck species (Long-tailed Duck and Velvet Scoter, Vulnerable on the IUCN Red List) was regularly occurring in Natura 2000 sites in Lithuania (Žydelis et al., 2009; 2013). In Mediterranean Spain, the Catalan coast is important foraging ground during the breeding season for the Critically Endangered Balearic Shearwater and the Vulnerable Yelkouan Shearwater. Bycatch of these species in the demersal longline fishery was known, and believed to be the most critical factor in the imminent extinction risk of the Balearic Shearwater (Genovart et al., 2016). In both countries our BirdLife Partners (Lithuanian Ornithological Society and SEO/BirdLife) were active on this issue and eager to participate in a collaborative approach with fishermen ideal conditions for the new Seabird Task Force. Our aim throughout the past 2.5 years has been to develop an active collaboration between the fishing sector and conservationists, in order to understand the bycatch problem in these high priority fisheries and develop technical solutions. This report details the progress towards these challenging goals. In Lithuania, we explore our efforts to test an experimental mitigation measure for gillnets a fishing gear where solutions to seabird bycatch do not currently exist. Our work in this country saw us directly participate with fishermen, trialling high contrast panels attached to their gillnets. Although our results showed that ultimately these panels are not effective in reducing seaduck bycatch, this work has provided vital insights into the bycatch issue and the potential for future work to solve the problem. In Spain, we outline our new understanding of bycatch in the complex demersal longline fishery (shared between medium-scale and artisanal small scale vessels). We also explain our progress towards developing a prototype mitigation measure– the adaptation of the Chilean vertical longline which shows real promise as part of a mitigation measure toolbox. The subsequent pages also reflect the hard work of our in-country Task Force teams, and the goodwill and collaborative spirit of the fishing communities in both countries. Our work would not have been possible without this effective collaboration, and we feel that such an approach is fundamental to finding these solutions. Our work also comes at an opportune time. In the EU, the new Data Collection Regulation was recently adopted and the European Commission's proposal on the Technical Measures Regulation (rules for EU fishing vessels to regulate their impact on the environment) will soon be negotiated. Our work clearly demonstrates that it is possible to find solutions alongside the fishing sector to solve the bycatch problem. We hope that the policy framework will reflect this possibility so that within the EU there are strong drivers for including bycatch mitigation on-board vessels. In Europe our work is far from finished, and we look forward to more hard work ahead and hopefully positive outcomes for both seabirds and the fishing community. https://seabirdbycatch.com/2017/09/29/seabird-task-force-report-released/ http://www.birdlife.org/europe-and-central-asia/pr/29-september-2017

Illegal fishing bycatch overshadows climate as a driver of albatross population decline

Article

Sep 2017

Effective management of albatross populations requires understanding the impacts of environmental factors on albatross demographics. An integrated modeling approach, incorporating multiple data sources, can further the understanding of albatross demographics by incorporating error from all components of modeling and distinguishing between variability related to one factor (e.g. environment) from that of another factor (e.g. density-dependence). We apply such an integrated, spatially-explicit population model to quantify the impact of environmental conditions (sea-surface temperature: SST), fisheries, and density-dependence on a black-browed albatross (Thalassarche melanophris) population breeding on Kerguelen Island, southern Indian Ocean for the period 1950-2011. The model is structured by sex, age-class, and breeding stage, with a 5 × 5 spatial scale and monthly temporal scale. All parameters are estimated within a maximum-likelihood framework. This includes estimation of the seabird bycatch rates of each of five fishing super-fleets, grouped by gear-type and reported bycatch rates: (i) Japanese pelagic longline, (ii) other pelagic longline, (iii) legal demersal longline, (iv) trawl, and (iv) illegal, unreported and unregulated (IUU) demersal longline. A decline in the Kerguelen black-browed albatross population occurred between the mid-1990s through the mid-2000s. Our analysis attributes the majority of modelled bycatch to the IUU demersal longline super-fleet operating near Kerguelen for this period. Including SST during the incubation period indicated that warm SST favors high breeding success. These results indicate that effective management requires an integrated understanding of the impacts of the environment, illegal, and legal fishing activities on vulnerable populations.

The conservation status and priorities for albatrosses and large petrels

Article

Sep 2016
BIOL CONSERV

Seabirds are amongst the most globally-threatened of all groups of birds, and conservation issues specific to albatrosses (Diomedeidae) and large petrels (Procellaria spp. and giant petrels Macronectes spp.) led to drafting of the multi-lateral Agreement on the Conservation of Albatrosses and Petrels (ACAP). Here we review the taxonomy, breeding and foraging distributions, population status and trends, threats and priorities for the 29 species covered by ACAP. Nineteen (66%) are listed as threatened by IUCN, and 11 (38%) are declining. Most have extensive at-sea distributions, and the greatest threat is incidental mortality (bycatch) in industrial pelagic or demersal longline, trawl or artisanal fisheries, often in both national and international waters. Mitigation measures are available that reduce bycatch in most types of fisheries, but some management bodies are yet to make these mandatory, levels of implementation and monitoring of compliance are often inadequate, and there are insufficient observer programmes collecting robust data on bycatch rates. Intentional take, pollution (including plastic ingestion), and threats at colonies affect fewer species than bycatch; however, the impacts of disease (mainly avian cholera) and of predation by introduced species, including feral cats (Felis catus), rats (Rattus spp.) and house mice (Mus musculus), are severe for some breeding populations. Although major progress has been made in recent years in reducing bycatch rates and in controlling or eradicating pests at breeding sites, unless conservation efforts are intensified, the future prospects of many species of albatrosses and large petrels will remain bleak.

Foraging distribution overlap and marine reserve usage amongst sub-Antarctic predators inferred from a multi-species satellite tagging experiment

Article

Full-text available

Nov 2016

Satellite telemetry data was used to predict at sea spatial usage of five top order and meso-predators; Antarctic fur seals (Arctocephalus gazella), macaroni penguins (Eudyptes chrysolophus), king penguins (Aptenodytes patagonicus), black browed albatross (Diomedea melanophrys), and light mantled albatross (Phoebetria palpebrata). All were tagged at Heard Island in the Southern Ocean over a single summer season collecting over 5000 tracking days for 178 individuals. We aimed to predict areas of likely high foraging value from tracking environmental data and also to quantify overlap in foraging range between species. Hidden Markov models were used to differentiate between bouts of Area Restricted Search (ARS) assumed to be associated with areas of higher foraging value, and transit behaviours. Oceanographic and distance metrics associated with ARS activity were then used to calculate a habitat electivity index. A combined bootstrap/Monte Carlo scheme was employed to propagate uncertainty from the Hidden Markov models into the habitat prediction scheme. Distinct differences were predicted in the spatial distribution of foraging locations in different species, reflecting different dispersive abilities and foraging strategy. The extent of usage and foraging distribution was largely contained within Australian the Economic Exclusion Zone (EEZ). In comparison, the smaller Australian Commonwealth Marine Protected Areas (MPAs) contained <20% of the predicted foraging distributions. Crown

Developing a climate adaptation strategy for vulnerable seabirds based on prioritisation of intervention options

Article

Jul 2016
DEEP-SEA RES PT II

Plan de Acción Nacional para Reducir la Captura Incidental de Aves Marinas en las Pesquerías Uruguayas, 2015

Chapter

Full-text available

Aug 2015

Revisión de Planes de Acción Nacional para la Conservación de Aves Marinas y Condrictios en las Pesquerías Uruguayas

Book

Full-text available

Jan 2015

Laysan Albatross on Guadalupe Island, México: Current Status and Conservation Actions

Article

Full-text available

May 2015

Guadalupe Island, off the Baja California peninsula, México, hosts the most important growing Laysan Albatross (Phoebastria immutabilis) breeding colony in the eastern Pacific. Since this seabird’s first arrival in 1983, it has been affected by predation from feral cats (Felis catus), present on Guadalupe since the late 19th century. Heavy predation events have been recorded on the island, so we initiated a feral cat control campaign in 2003 and began collecting baseline information for developing an eradication plan. At the same time, we conducted seasonal monitoring of Laysan Albatross reproductive success in order to assess the benefits from control activities. Cat relative abundance on Guadalupe was estimated through spotlight surveys, and control was done at the southernmost end of the island around the 2 locations where Laysan Albatross nest: Colinas Negras and Punta Sur. Laysan Albatross population growth rate was calculated based on the number of reproductive individuals, while breeding success was estimated as the proportion of laid eggs that resulted in fledged chicks. A total of 203 cats were removed from the south end of Guadalupe between 2003 and 2013. During this same period, high reproductive success (0.8) was recorded for Laysan Albatross, suggesting a positive effect of cat control activities. We found significant differences in reproductive success between years with predation and no predation by feral cats. The Laysan Albatross colony on Guadalupe has grown steadily during the past 30 years, increasing from 4 to 143 breeding pairs between 1984 and 2013, respectively, and with a population growth rate of 1.10 between 2004 and 2013.

Genetics informs the origin of black-browed albatross at a new breeding site in Chile

Article

Full-text available

Dec 2024
POLAR BIOL

A small colony of black-browed albatrosses (Thalassarche melanophris, 21–65 breeding pairs) was discovered in 2003 on Albatross Islet, Tierra del Fuego, Chile. The formation of new breeding sites is important from an ecological and evolutionary perspective. This colony is particularly significant because it is the only one recorded for the species in a land-locked area. As its population dynamics could be shaped by stochastic and other factors affecting small populations, understanding the variables influencing its persistence, such as source of breeders, is crucial. Here, we used genetic markers (mitochondrial control region) to determine the origin of individuals at this new breeding site. Our results show that the new colony is an even mix of birds from Chilean colonies to the south and west (52%) and Falklands/Malvinas birds to the east (48%). Understanding the unique characteristics of this colony provides valuable insights for the conservation of black-browed albatrosses given increasing anthropogenic and environmental changes.

Two lenses for exploring relationships between seabirds and fishers: Unveiling reciprocal contributions

Article

Full-text available

Aug 2024

Reciprocal relationships between fishers and marine life have been documented in Indigenous fishing contexts, but there are few case studies that describe the mechanisms of such relationships, and even fewer that explore other contexts, such as that of artisanal fishers in Latin American countries. We studied the artisanal hake fishery in the sub‐Antarctic channels of Chilean Patagonia, a global hotspot for albatross and petrel diversity. We aimed to uncover nature's contributions to hake fishers and, reciprocally, the potential fishers' contributions to marine life with a particular emphasis on seabirds. We adopted a bifocal observational strategy. From a human perspective, ethnographic methods (e.g., semi‐structured interviews) are analysed with Nature's Contributions to People and reciprocal contribution frameworks. From the seabirds' view, we assessed offal consumption through experimental and observational methods. We randomly threw offal items into the sea and observed the seabird responses (whether they consumed offal). Hake fishers' relationships with the marine environment are multidimensional, particularly with seabirds. Based on fishers' perceptions, we identified four key contributions of seabirds to humans: they serve as value indicators of fishing distribution and concentration areas, offer companionship and recreation during fishing activities, enhance scenic emotionality through the presence of albatrosses and assist in the function of sea cleaning. In reciprocal contributions, artisanal fishers viewed hake offal as a beneficial food source for the seabirds, especially the liver. Fishers described that fishing in the right way can reduce bycatch and effort. The fishers' main contribution to seabirds is through offering them the offal of hake catches. We observed that seabirds consumed hake liver 99% of the time, while they consumed stomach less frequently (24%). We identified that southern giant petrels and black‐browed albatrosses consumed more liver, while kelp gulls ate more stomach. The liver comprises 51.6% fat, essential for high trophic level marine predators such as black‐browed albatrosses. Adopting reciprocal contributions and NCP served as a catalyst for understanding fishers' positive actions but also is a promoter to research multiple views of nature–human relationships in fishing settings. Values of nature, like reciprocity, could enrich ecosystem‐based management strategies. Read the free Plain Language Summary for this article on the Journal blog.

Impact of wind on collision mortality in grey-headed albatrosses Thalassarche chrysostoma breeding on Marion Island

Preprint

Full-text available

Mar 2023

Albatrosses exploit winds to travel vast distances across the ocean. Their morphology is adapted for low-cost dynamic soaring flight, but these adaptations confer low manoeuvrability, which may be risky when flying over land. This study investigates how wind conditions influence Endangered grey-headed albatross Thalassarche chrysostoma crashes in the valley below an inland sub-colony on Marion Island. Carcass surveys were conducted in a 1 km ² area spanning the length of this sub-colony (ca. 4000 breeding pairs) from October 2017 to June 2021. Hundreds of adult and fledgling albatross carcasses were discovered, some with evidence of fatal crash-landings in the form of broken bones. Wind data measured on the cliff-top above the colony were supplemented by computational fluid dynamics simulations of wind vectors over Marion Island. Most crashes occurred below the centre of the colony, where there are strong gradients in wind speed and direction under the dominant westerly wind conditions. Observations of albatrosses in flight indicate that most birds are killed when attempting to leave the colony, specifically when flying low above ground in strong wind. An average of at least 41 adults and 40 fledglings died after crashing into the valley annually. This represents an estimated 2% of the annual production of fledglings, 0.5% of the estimated annual breeding adult population and 11% of the adult annual mortality, suggesting a substantial cost to breeding at this inland site. For these long-lived seabirds, even low levels of adult mortality can have potential demographic consequences. This is the first study to document persistent wind-driven, land-based mortalities in albatrosses.

Albatross and petrel interactions with an artisanal squid fishery in southern Peru during El Niño, 2015-2017.

Article

Full-text available

Mar 2022

We report on the occurrence of albatrosses (Diomedeidae) and petrels (Procellariidae) associated with an artisanal small-scale fishery (SSF) for Humboldt Squid Dosidicus gigas in waters of southern Peru during El Niño 2015–2016 and coastal El Niño 2017. We deployed as observers on a number of fishing trips to assess seabird interactions. White-chinned Petrels Procellaria aequinoctialis and Waved Albatross Phoebastria irroata were the most abundant species observed, followed by Salvin’s Thalassarche salvini and Chatham albatross T. eremita, and Cape Petrels Daption capense. The majority of procellariid species (> 60% of total birds) visited while vessels were positioned over the continental slope. Salvin’s and Chatham albatross, and White-chinned Petrels, were mostly absent during summer (only 5% and 15% of birds present, respectively), but Waved Albatross and Cape Petrels were present year-round. Thus, the prevalence of each of these species was disproportionate relative to expectation based on non-fishery surveys. All assessed species foraged on offal discards associated with the fishery (~17%), with a higher frequency of consumption among Salvin’s (27%) and Chatham (21%) albatross; in contrast, Waved Albatross largely fed on pelagic fish at the surface. Bycatch rate was found to be low: one Chatham Albatross was hooked and released in a hand-held squid jig (0.042 By Catch Per Unit Effort [BPUE] per fishing trip, n = 16). Probably due to El Niño conditions, Waved Albatross were more abundant than expected (43.9% of albatross, and 2.8% of total seabirds observed) and were 1 300–1 400 km farther south than their usual southern limits. We report the first sighting of Southern Royal Albatross Diomedea epomophora in Peru. Bycatch in longline fisheries are a conservation concern, but the magnitude and constant growth of SSFs, especially for Humboldt Squid, needs to be further investigated.

Extinctions

Chapter

Oct 2020

Until recently, animal and plant extinctions were limited to ocean islands. Sadly, extinctions now have arrived on continents, as human populations have rapidly grown, enormous areas of natural habitat converted to agricultural land, hunting for food and poaching for “fake” medicines and jewelry increased, introduction of alien species expanded, and resource consumption and pollution have increased since WWII and exploded since the 1990s acceleration in globalization and global income disparity. Today 83% of all animals are domestic, while the loss and fragmentation of natural habitat and space is critically endangering much of the wildlife that is left. Poaching for elephant ivory, rhino horn, pangolin scales, and helmeted hornbill’s casque is at all-time high. Additionally, bush-meat consumption is contributing to the emergence of new pathogens.

Not all seabird species can overcome marine threats when predator removal at their colonies is prioritised

Preprint

Sep 2019

Seabirds are globally threatened. In the face of multiple threats, it is critical to understand how conservation strategies that mitigate one threat intersect with others to impact population viability. Marine threats, including pollution, climate change, and fisheries could derail gains to seabird populations resulting from arduous predator eradication efforts. However, this potentially negative effect is yet to be evaluated. We test whether mortality from marine threats can subvert the on-going recovery of 17 seabird species from 37 colonies on islands worldwide where predators were removed. We use demographic modelling to estimate potential adult mortality from fisheries, plastic ingestion, and climate change. For 82% of the species we examine, marine threats do not impede recovery following predator eradication. However, for six colonies of three species, Calonectris diomedea, C. borealis, and Ardenna carneipes, mortality from multiple marine threats may interrupt their recovery. Combining our demographic approach with comparative phylogenetic methods, we explore whether foraging niche, range, and morphometric traits inform the vulnerability to marine threats using an expanded dataset of 81 seabird species. Our analyses reveal surface filtering and pursuit diving species, and species with smaller at-sea distributions to be most vulnerable to declines due to multiple threats. However, these traits do not necessarily predict species vulnerability to marine threats in the absence of predators at nesting colonies, suggesting that shared traits may not be useful to infer vulnerability to multiple marine threats. Post-eradication monitoring to determine whether species require additional conservation management following predator eradication are essential in the face of intensifying pressures in the marine environment.

Albatross chicks reveal interactions of adults with artisanal longline fisheries within a short range

Article

Jun 2018

Incidental capture in fisheries (“bycatch”) is a major threat to global marine biodiversity, especially to those species with low fecundity, such as albatrosses. Efforts to reduce bycatch have been undertaken in industrial fisheries, but the scale of seabird interactions with artisanal or small-scale fleets remains largely unknown. The island of Torishima (Japan) is an important breeding site for two albatross species (short-tailed Phoebastria albatrus and black-footed P. nigripes) and also lies in the range of the artisanal longline fishery for the splendid alfonsino Beryx splendens. In February–March 2017, we tracked 23 foraging trips of adult P. nigripes feeding chicks by Global Positioning System (GPS) and monitored the prevalence of fishing gear at the nests using a metal detector. The foraging range of these albatrosses was a maximum of 280 km from Torishima, and only 3.7% of the GPS locations occurred over the shallow habitats targeted by the alfonsino fishery (water depth 150–500 m), suggesting relatively low risks of interaction. However, 190 (54.3%) nests of P. nigripes contained fishing gear, among which 12 (3.4%) nests or chicks contained a hook or an unidentified metallic object. Six hooks were also collected from P. albatrus nests. All found hooks, except one, originated from the alfonsino fishery, indicating that both targeted albatross species actually interacted with this fishery at sea. Both research approaches provided data from returning birds only and did not reflect possible lethal cases at sea. Monitoring the sub-lethal effects of bycatch and encouraging small-scale fisheries to report gear lost at sea are two possibilities to further help quantify and reduce the impact of fisheries on seabirds.

Collaboration on technical innovation towards the reduction of seabird bycatch in purse seine fisheries

Working Paper

May 2016

Purse seine fisheries are widely common in the seas of the world. However, this is one of the least attended in bycatch of non-target species such as seabirds, in contrast to international attention focused in longline, trawl and gillnet fisheries. During characterization of bycatch in small-scale purse seine fisheries (length ≤15m) for Anchoveta in the north (~18° S) and Sardine in south-central Chile (~37° S), we identified from complete sets (n=73), different net’s hotspots of negative interaction with seabirds. These affected plunge divers such as boobies and pelicans (north) and pursuit as shearwaters (south-central). As sources of bycatch, we identified a high hanging ratio of net (>45%), resulting in: i) drowning of divers due the presence of ceiling of the drifting body and cod of net during setting, and ii) entanglement and trauma of divers with net folds by this excess of net during hauling. We also identified entangled birds on zippers (connectors between net and buoys) and ropes of the buoy line during hauling. In south-central Chile, we recorded 12 seabird species associated to setting and 6 species during hauling. Among these, the recently listed ACAP species Pink-footed and Sooty shearwaters (81% and 19%, respectively) reached a maximum combined bycatch of 3.58 birds/setting, 7.62 birds/trip. Since 2014, we have begun a collaborative initiative with fishermen and net industry to carrying out experimental trials of a modified net with reduced hanging ratio, zipper and size of rope sinus attached to the buoy line. When compared in a first stage of simultaneous sets (n=39) with control nets (hanging ratio >40% and zippers between 21⁄2 - 31⁄2 inches of mesh size), treatment (modified) net has presented no mortality associated with the modified gear hotspots versus 0.55 birds/setting, 1.11 birds/trip as recorded for sets with control (unmodified) nets.

Drivers of variation in the migration and foraging strategies of pelagic seabirds

Thesis

Sep 2017

Thomas A. Clay

The ability to move and forage efficiently plays a major role in determining the fate of individuals, and has important implications for population dynamics and ecosystem functioning. Migration is a particular type of movement strategy, whereby animals may travel remarkable distances in order to take advantage of seasonality in resource availability or to avoid arduous winter conditions; however, this can be at a cost in terms of increased mortality. Indeed, anthropogenic threats in non-breeding areas are a major cause of population declines and a better understanding of non-breeding spatial ecology is required in order to advance both ecological theory and conservation management. The recent development of animal tracking technologies, in particular light-based geolocation, has made it possible to track large-scale and long-term movements; however, there are still gaps in our knowledge, such as the links between migratory and reproductive performance, connectivity among populations and the ontogeny of migration strategies. In this thesis, I utilise multi-species and longitudinal datasets from albatrosses and petrels, some of the most mobile species on Earth, to explore the drivers of variation in movements, habitat use and foraging behaviour, and the implications for life history and conservation. In Chapter 1, I provide an overview of the key topics of this thesis. In Chapter 2, I provide quantitative recommendations of minimum sample sizes needed to track pelagic seabird migrations, using data from 10 species. In Chapter 3, I examine between- and within-population differences in the habitat preferences and distributions of albatrosses, including the relative roles of habitat specialization and intra-specific competition. In Chapter 4, I investigate the year-round movement and foraging strategies of petrels living in nutrient-poor environments. In Chapter 5, I examine potential links between foraging behaviour during the non-breeding season and reproductive senescence. In Chapter 6, I explore the ontogeny of foraging behaviour and foraging site fidelity in young albatrosses, shedding light on their “lost years” at sea. Finally, I conclude with a general discussion summarizing main findings and suggesting future work. Overall, my results highlight the complex relationships among individual traits, the environment, movements and foraging behaviour, and population dynamics across the lifespan of individuals, with implications for the conservation of this highly threatened group of species.

Emerging platforms to monitor the occurrence and threats to critically endangered seabirds: The waved albatross in Chile and the Southeast Pacific

Article

Full-text available

Aug 2017

Long-lived seabird species such as albatrosses and petrels, which are widely distributed at sea and have small populations are threatened globally by bycatch in fisheries. Among these, the waved albatross Phoebastria irrorata is scarcely detected in the Exclusive Economic Zones (EEZs) of countries beyond its traditional distribution throughout the Southeast Pacific. In this article, in situ distributional records on the waved albatross obtained from non-systematic (pelagic birdwatching) and systematic (fishery monitoring) records were compiled. Occurrence of sightings was carried out in relation to recording traits as presence/absence of breeding period and El Niño proxies such as the Southern Oscillation Index (SOI), among others. A total of 13 sightings of waved albatrosses was described which 76.9% of sightings were related to non-breeding period (December to April). Records indicated waved albatrosses reached 4,391 km south of the Galapagos Islands (38°S) and 920 km west of the South American coast (79°W). The waved albatross was associated with industrial pelagic longline and demersal trawl fisheries, and although there were no records of bycatch, the observation of individuals feeding on discards and offal suggests a potential risk of mortality for this species. 53.8% of sightings were during positive readings of the Southern Oscillation Index (SOI), representing colder conditions than neutral El Niño Southern Oscillation (ENSO).

Albatrosses prospect before choosing a home: intrinsic and extrinsic sources of variability in visit rates

Article

Jun 2017

In long-lived species with delayed maturity, prebreeders are expected to gather information by visiting and sampling the quality of potential nesting areas (prospecting), before they choose where to breed. In most seabirds, this process is important because, once recruited, individuals generally remain site-faithful throughout their long reproductive life. As many seabirds are believed to display low levels of natal dispersal, it is possible that natal philopatry is an obligate strategy for most individuals, with prospecting being a negligible activity during the prebreeding stage. Using ringing information and GPS technology, we tracked breeding adults and prebreeder black-browed albatrosses, Thalassarche melanophris, from a colony of the Falkland Islands, during the breeding season. Breeding adults rarely engaged in prospecting, whereas prebreeders showed a high propensity to visit other colonies. Most prebreeders started prospecting ashore when 4–5 years old and most of the younger individuals prospected more than one breeding colony, with some prospecting up to five colonies in just 9 days. Prospecting activity did not differ between males and females and rapidly declined as prebreeders aged, by which time individuals had probably already selected their future nesting site. Nestling body mass at 60 days of age and hatching date did not influence prospecting behaviour later in life. Prospecting was mostly directed at colonies within 10 km from the natal place, but occurred regularly up to 55–65 km. While distance from the natal place was a strong predictor of the probability of a colony being prospected, colony size and growth rate were not. Our results provide new insights into the role of prospecting in the process of recruitment, showing that even for highly philopatric birds, recruitment to the natal colony (or to another nesting site) has the potential to be informed, not done blindly.

Ecosystem Oceanography of Seabird Hotspots: Environmental Determinants and Relationship with Antarctic Krill Within an Important Fishing Ground

Article

Full-text available

Aug 2017
ECOSYSTEMS

The discipline of ecosystem oceanography provides a framework for assessing the role of mesoscale physical processes on the formation and occurrence of biological hotspots. We used shipboard surveys over nine years to investigate environmental determinants of seabird hotspots near the Antarctic Peninsula, a region experiencing rapid climate change and an expanding krill fishery. We hypothesize that seabird hotspots are structured by mesoscale ocean conditions that reflect differences in prey distribution within oceanic and coastal waters. We used generalized additive models to quantify functional relationships of seabird hotspots with krill biomass, and a suite of remotely sensed environmental variables, such as eddy kinetic energy. The spatial organization, changes in intensity, and distribution shifts of seabird hotspots indicate different environmental drivers within coastal and oceanic domains and reflect the seasonal variability of the ecosystem. Our results indicate at least eight mesoscale hotspot zones that represent ecologically important areas where significant krill and predator biomass may be concentrated. Our ecosystem assessment of seabird hotspots identified critical foraging habitat and provided reference points to benefit research on estimating their trophic impacts on Antarctic ecosystems and potential effects from the krill fishery. Our approach is generally applicable to other pelagic ecosystems that are structured by hydrographic fronts and eddies, and containing schooling forage species shared by multiple wide-ranging predators. Furthermore, identification of biological hotspots is useful for the designation of marine protected areas most critical to potentially endangered wildlife and fisheries resources.

WWF Tracking Antarctica - An update on the state of Antarctica and the Southern Ocean

Research

Full-text available

Oct 2016

Tracking Antarctica is a WWF report on the latest science of the Antarctic. It identifies and explains critical threats such as climate change on Antarctic biodiversity including krill, whales, seals and seabirds. The report highlights progress made on IUU (illegal) fishing and sustainable solutions to adapt to global change.

Exploratory fishing for Dissostichus spp. in the Antarctic region (Subareas 48.1, 48.2 and 88.3)

Article

Full-text available

Jan 1999

During February and March 1998, a 43-day cruise on FV Tierra del Fuego was conducted as part of the New Fisheries Projects developed by Chile, primarily to establish the presence of Dissostichus spp. in Subareas 48.1, 48.2 and 88.3. Industrial longlines (Spanish system) were used for the operation, with variable quantities of fish hooks (1 440 to 4 320), No. 9 Mustad Kirby type, set between depths of 600 and 2 550 m. Sardines (Sardinops sagax) and squid (Illex argentinus) were used as bait. Antarctic toothfish (Dissostichus mawsoni) were recorded around Peter I Island (Latitude 68°49′S), and from the Bellingshausen Sea (70°38′S) to Clarence and Elephant Islands (61°14′S), while Patagonian toothfish (Dissostichus eleginoides) were caught in waters from King George Island in the South Pacific Ocean (61°24′S) to the Scotia Sea in the South Atlantic (58°03′S). Yields of Dissostichus spp. were very low in the three subareas, with values of only 5.7 g/hook (Subarea 88.3), 19.1 g/hook (Subarea 48.1) and 3.0 g/hook (Subarea 48.2), and an average over all areas of 11.1 g/hook.

Una nueva colonia de anidamiento para el albatros de ceja negra (Thalassarche melanophrys) para Chile

Article

Full-text available

Jan 2007

We describe a new colony of Black-browed Albatrosses (Thalassarche melanophrys) from the Magallanes region, southern Chile. The colony was located at Islote Leonard (55°23' S 74°04' W) with a population of 594 breeding pairs. We also did measure some eggs and comments on other colonies mentioned on the literature such as Evout and Noir islands. The total approximated number of breeding pairs for Chile is 49,142 a 34.8 % higher than estimated by Gales (1998) and 42% lower than estimated by Clark (1992).

EFECTOS DE LAS PESQUERÍAS INDUSTRIALES DE PALANGRE SOBRE LAS AVES MARINAS Y EL CAMINO A SU MITIGACIÓN EN CHILE. (Book chapter)

Book

Full-text available

Nov 2006

Carlos A. Moreno

Los efectos humanos directos e indirectos sobre la fauna marina afectan más signifi cativamente las especies que pre-sentan mayores tamaños corporales, gran longevidad, baja fecundidad y tamaños de poblaciones pequeños (miles en vez de millones). Este tipo de organismos suelen ser depre-dadores de alto nivel trófi co, mientras que las especies de pe-queño tamaño corporal suelen tener poblaciones mucho más abundantes (millones de individuos en vez de miles) ubica-das más abajo en las cadenas alimentarias marinas. Así los impactos —pesca o caza— que han acercado a la extinción a organismos marinos han sido sobre grandes mamíferos ma-rinos como las ballenas, grandes peces como el mero y entre las aves marinas mayores como los albatros y petreles. Efectivamente, estos últimos presentan longevidades muy altas; por ejemplo el albatros errante puede vivir más de 60 años, con primeras reproducciones a los 9 a 15 años. Un al-batros chileno de cabeza gris o el de ceja negra puede vivir más de 50 años y su primera reproducción ocurre entre los 7 y los 12 años. Los petreles gigantes (pájaro carnero) presen-tan longevidades similares. Las especies de este grupo de aves varían desde los 40 cm de envergadura alar (golondrinas de mar) hasta los 3,50 metros (albatros errante, el ave voladora más grande del mundo). Este orden se divide en dos grandes grupos: albatros (familia Diomedeidae) y petreles (familias Procellariidae, Hydrobatidae y Pelecanoididae). Todos están muy bien adaptados al vuelo y al medio marino, pero nidifi can en tierra. En el hemisferio sur los albatros tienen una mayor di-versidad que en el hemisferio norte (19 especies v/s 3, respecti-vamente, más una especie que habita en el ecuador). Debido a las grandes distancias que recorren en busca de alimento (son esencialmente carroñeros), dependen mucho de los vientos y por eso sus colonias son más abundantes entre los paralelos 45 y 55 grados sur, entre los frentes subtropical y polar antártico. Pueden cubrir grandes distancias planeando con sus largas y angostas alas y suelen seguir los buques por días. Presentan un olfato extraordinario, asociado a sus gran-des narinas externas, que les ayuda a detectar un calamar o pez muerto en la superfi cie. Su olfato y su buena visión les permiten detectar los barcos de pesca desde grandes distan-cias. Debido a la inherente baja disponibilidad de alimento en los ambientes oceánicos en que deambulan, la oferta de carnadas desde los barcos de pesca constituyen su mayor amenaza, ya que inexorablemente al comerla quedan engan-chadas y se hunden con la línea (espineles o palangres) que retiene los anzuelos. Actualmente 97 especies de aves marinas —de un total de 337— se encuentran en la categoría de " amenaza de extinción global " , lo que representa un 29 por ciento de las aves marinas presentes en el mundo. Debido a lo anterior ha existido una preocupación mun-dial por salvar estas aves de su mayor amenaza; la industria pesquera de palangre, particularmente de especies demer-sales y pelágicas de peces de alto valor como el bacalao de profundidad, los peces espada y atunes. Por ejemplo, el baca-lao de profundidad (Dissostichus eleginoides) se pesca en el talud continental subantártico y antártico por todos los países del hemisferio sur: Australia, Sudáfrica, Uruguay, Argentina, Chile y Nueva Zelanda. Por otra parte, fl otas palangreras de altura de países con conocida tradición pesquera también se aventuran en estas aguas: Japón, Corea, España, Rusia, Namibia, China. Muchas de estas fl otas están o estuvieron involucradas en pesca ilegal, No reportada o No regulada —IUU, por sus siglas en inglés— donde se pesca sin ninguna consideración a la conservación del recurso objetivo ni de las especies capturadas incidentalmente (by-catch), inclu-yendo las aves y los mamíferos marinos. MORTALIDAD INCIDENTAL EN CHILE

Global seabird bycatch in longline fisheries

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Jun 2011

Bycatch in longline fisheries is believed to govern the adverse conservation status of many seabird species, but no comprehensive global assessment has been undertaken. We reviewed the extent of seabird bycatch in all longline fisheries for which data are available. Despite the many inadequacies and assumptions contained therein, we estimated that at least 160 000 (and potentially in excess of 320 000) seabirds are killed annually. Most frequently caught are albatrosses, petrels and shearwaters, with current levels of mortality liable to be unsustainable for some species and popula- tions. Where realistic comparisons can be made, with data from the 1990s, there is evidence of sub- stantially reduced bycatch in some key fisheries. Reductions stem from decreased fishing effort (especially in illegal, unreported and unregulated fishing in the Southern Ocean), and greater and more effective use of technical mitigation measures, notably in demersal fisheries. However, bycatch problems in other fisheries have also emerged. Current concerns include those with previously unidentified bycatch problems (e.g. Spanish Gran Sol demersal fleet) and those where bycatch was identified, but where persistent data gaps prevented adequate assessments of the scale of the impact (e.g. Nordic demersal fisheries). Future assessments will only achieve greater precision when mini- mum standards of data collection, reporting and analysis are implemented by longline fishing fleets and the relevant regional fishery management organisations. Those fisheries in which bycatch has been substantially reduced demonstrate that the problem of seabird bycatch could be reduced to negligible proportions by enforced implementation of appropriate best-practice mitigation devices and techniques.

An assessment of the population trends and conservation status of Black-browed Albatrosses in the Falkland Islands

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Jan 2012

Anton Carl Wolfaardt

The most recent archipelago-wide surveys of Black-browed Albatrosses breeding at the Falkland Islands were conducted in 2010, five years after the previous census. Different methods, principally aerial and ground-based surveys, have been used independently to census the population at the Falklands Islands. Previously these census initiatives reported contrasting population trends. The aerial based surveys indicated an increase in the population between 1986 and 2005 and the ground based surveys a decline between 2000 and 2005, and using historical data an inferred decline between 1995 and 2005. The aerial and ground-based surveys conducted in 2010 both revealed an increase in the Black-browed Albatross population of at least 4% per annum between 2005 and 2010. Although there are survey-specific differences in the population estimates and the percentage change patterns in the population, the positive trend from both these surveys is supported by demographic data and an additional aerial photographic survey conducted later in the 2010 breeding season than the aerial initial survey. The results from the 2010 ground-based survey indicate that the population has also increased since the first archipelago-wide ground survey in 2000, and possibly even since the initial ground based surveys were conducted at Beauchêne and Steeple Jason islands in the 1980s. Current estimates for the annual breeding population in the Falkland Islands range between 475, 500 and 535,000 breeding pairs. The exact reasons for the increase are not entirely clear, but efforts to reduce seabird bycatch and favourable feeding conditions are likely to have contributed. Given the favourable conservation status of Black-browed Albatrosses in the Falkland Islands, which comprise c. 70% of the global total, consideration should be given to downlisting the species from Endangered. Efforts should also continue to further improve seabird bycatch mitigation, both to buffer the local population against possible future changes, and to improve the conservation status of other populations and species. Introduction The Black-browed Albatross has since 2003 been classified as Endangered by the IUCN. The species has been assessed as Endangered on the basis of reported declines at large breeding colonies in the south-west Atlantic – principally those in the Falkland Islands and South Georgia – and so meets the criterion of declining at a rapid rate over three generations (BirdLife International 2012). An estimated 67-70% of the global population breeds in the Falkland Islands (ACAP 2010, BirdLife International 2012). Consequently, the global conservation status of the species is critically dependent on the status and trends of the Falkland Islands' population.

Determinación de los factores que inciden en la captura incidental de aves marinas en la flota palangrera pelágica chilena

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Sep 2012

We analized the relationship between the variability in the rate of seabird bycatch in pelagic longline fishery for swordfish (Xiphias gladius), and several temporary, environmental, spatial and fisheries factors for the fishing period from 2007 to 2009. The results show that the fishing operations of this fleet mainly affect the albatross, group that accounts for 83.7% of the incidental catch of seabirds recorded in the period. This bycatch is due primarily to the presence of the South Pacific Subtropical Front, a system that causes the overlap between the activities of this fleet with the spatial distribution of these seabird species during the resident phase of the nonbreeding period. By the other hand, the variability in bycatch would be strongly linked to visual stimuli (measured by the percentage of chemical lights and percentage of squid) and the existing ambient lighting conditions during the set (measured by the lag time of sunset with respect to time start set and lunar phase).

Experimental fishing with an “umbrella-and-stones” system to reduce interactions of sperm whales (Physeter macrocephalus) and seabirds with bottom-set longlines for Patagonian toothfish (Dissostichus eleginoides) in the Southwest Atlantic

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Jan 2011

Goetz, S., Laporta, M., Martínez Portela, J., Santos, M. B., and Pierce, G. J. 2011. Experimental fishing with an “umbrella-and-stones” system to reduce interactions of sperm whales (Physeter macrocephalus) and seabirds with bottom-set longlines for Patagonian toothfish (Dissostichus eleginoides) in the Southwest Atlantic. – ICES Journal of Marine Science, 68: 228–238. Depredation, i.e. the damage or removal, of Patagonian toothfish (Dissostichus eleginoides) from longlines by sperm whales (Physeter macrocephalus) can cause considerable economic loss for Spanish fishing vessels in the Southwest Atlantic. The fishery also suffers high bycatch rates of seabirds. The main goal of the study was to assess the extent of depredation and seabird bycatch and to test the potential of the so-called “umbrella” system, coupled with attached stones for faster sinking, for minimizing both. Moreover, we investigated the relationships between sightings of sperm whales, depredation, catches, and environmental variables using generalized additive modelling. Data were collected during 297 hauls on a longliner in 2007/2008 in international waters of the Southwest Atlantic. Sperm whales were sighted during 35% of the hauls, always during gear retrieval, and their presence was positively related to fish damage. The overall depredation rate (0.44% of the total catch) was low, but is assumed to be underestimated because sperm whales were suspected of also taking fish without leaving visual evidence. The “umbrella-and-stones” system was highly effective in preventing bycatch and appeared to restrict depredation, but significantly reduced the catches. The results demonstrate that there is still some way to go to solve the problem of depredation.

Nuevo sitio de anidamiento del albatros ceja negra, Diomedea melanophris Temmink 1828, en el Seno Almirantazgo, Tierra del Fuego, Chile

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Jan 2003

ANTECEDENTES Los lugares de reproducción del alba-tros de ceja negra, Diomedea melanophris Temmink 1828 (Aguayo-Lobo et al. 2001, infor-man sobre el nombre genérico usado por otros autores), conocidos hasta el momento en el país, corresponden a las islas Diego de Almagro, islas Ildefonso e isla Diego Ramírez (Pisano 1972, Clarke et al 1992, Schlatter & Riveros 1997, Gales 1998, Aguayo-Lobo et al 2001) (Fig. 1). Para el hemisferio sur, las poblaciones nidificantes del albatros ceja negra fueron informadas por Gales (1998). Las principales se ubican en las islas del Atlántico sur occidental, como islas Malvinas con 548.924 parejas reproductivas, Georgia del Sur con 96.252 parejas; seguida por las que se ubican en el Pacífico sur oriental (Chile) como isla Diego de Almagro, islas Ildefonso y Diego Ramírez, con una población que suma 51.000 parejas. Los grupos reproductivos se agrupan después en las islas Crozet, Kerguelen, McDonald, Heard y Macquarie, en el océano Índico, sumando allí 5.013 parejas. Los grupos reproductivos reproductivos más pequeños son los que se dis-tribuyen en el océano Pacífico occidental como islas Snares, Campbell y Antípodas que sólo su-man 131 parejas reproductivas. De lo anterior se desprende que de las 701.320 parejas reproductivas de todo el hemisfe-rio sur, sin considerar a las islas Malvinas, en las islas chilenas se reproducen el 35,8% de las 142.396 parejas reproductivas restantes. En consecuen-cia, encontrar un nuevo sitio de anidamiento del albatros ceja negra en islas chilenas es importan-te comunicarlo a la comunidad científica. Área de estudio Bahía Azopardo se encuentra en el ex tremo oriental de Seno Almirantazgo. En su saco se localiza la caleta Benavente donde desemboca el río Azopardo que tiene su origen en el lago Fagnano (Anónimo 1991). El islote innominado al que denominaremos islote Albatros, se encuen-tra en bahía Azopardo, entre la isla Tres Mogotes y la caleta Benavente, hallándose un poco al norte del eje de la bahía mencionada (Fig. 1). El pequeño islote Albatros se

An experimental assessment of factors affecting the sink rates of Spanish-rig longlines to minimise impacts on seabirds

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Dec 2007
AQUAT CONSERV

1. The Spanish system of longline fishing is used in a range of demersal and semi-pelagic fisheries throughout the southern hemisphere and has been the source of a large number of seabird fatalities. An experiment was conducted on a chartered Spanish-rig vessel to increase the sink rate of longlines to reduce interactions with seabirds. 2. The experiment examined the effect of setting speed, distance between line weights and the weight of the line weights on the sink rates of hook lines. 3. The most powerful effect was line weighting, which affected sink rate independent of setting speed and distance between weights. Distance between weights was also important, but its effect depended on setting speed. Overall, however, the effect of setting speed was minor and the principal determinants of sink rates were the mass of the weights and distance between the weights. 4. Based on published accounts of seabird mortality in Spanish system fisheries, 8 kg/30 m is the preferred weighting regime to minimize interactions with seabirds. Sink rates from this regime are the fastest that can be expected from Spanish system gear without overly compromising fishing operations. Used in combination with bird scaring streamer lines and the slower setting speeds the weighting regime has the potential to reduce mortality of albatrosses and deep diving seabird species to very low levels.

Factors Affecting the Incidental mortality of Seabirds in the Dissostichus eleginoides Fishery in the Southwest Atlantic (Subarea 48.3,1995 Season)

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Oct 1996
CCAMLR SCI

This paper analyses all incidental mortality of seabirds recorded on Argentinian and Chilean vessels fishing for Patagonian toothfish (Dissostichus eleginoides) in Subarea 48.3 during the 1995 season. The data was obtained from the fine-scale reports submitted by each vessel to its national fishing authority and supplemented with the information collected by international scientific observers from each vessel. It was thus possible to evaluate almost all of the incidental mortality of seabirds observed during the season. The total mortality recorded was 1 428 birds of which white-chinned petrels (Procellaria aequinoctialis) comprised 77.8%, southern giant petrels (Macronectes giganteus) 10.8%, black-browed albatrosses (Diomedea melanophris) 8.1%, wandering albatrosses (D. exulans) 2.0% and grey-headed albatrosses (D. chrysostoma) 0.7%. A total of 56 seabirds captured during hauling operations and released alive was also recorded. Within this group, the most abundant were M. giganteus (50%), D. melanophris (14.3%) and P. aequinoctialis (8.9%). A study of the variables affecting incidental mortality shows that the distance from land, the lunar phase and the use of streamer lines and hook size were important sources of variation, both in vessels' analyses of catch of birds per unit effort (BPUE), as well as of the haul-by-haul data.

Line weights of constant mass (and sink rates) for Spanish-system Patagonian toothfish longline vessels

Article

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Aug 2008
CCAMLR SCI

CCAMLR Conservation Measure 25-02 requires Spanish-system longline vessels to attach 8.5 kg weights at 40 m intervals on longlines to minimise interactions with seabirds. The weights typically used are collections of rocks enclosed in netting bags. During fishing operations the netting bags abrade on the seabed causing rocks to be lost and the weights to become progressively lighter, requiring ongoing repair. This problem can be solved by use of hydrodynamically shaped (e.g. torpedo-shaped) steel weights, which are smaller for equivalent weight, and require no maintenance. An experiment was conducted on a Spanish-system longline vessel to determine the relationship between the sink rates of longlines equipped with bags of rocks (4, 6 and 8 kg) and those with steel weights of equivalent masses. The purpose of the experiment was to provide vessel operators with the option of substituting steel weights for rock weights while remaining in compliance with the sink rates associated with the line-weighting provisions of Conservation Measure 25-02. Both the Spanish system and the newly developed Chilean longline (a modified version of the former method to avoid fish loss by toothed whales) were tested in the experiment. Spanish-system longlines with 8 kg rock weights every 40 m averaged 0.22 m s-1 to 2 m depth, which would be equal to, or exceeded by, lines with 5 kg steel weights. Sink rates of Chilean longlines greatly exceeded those of the Spanish system, ranging from 0.68 m s-1 (4 kg rocks) to 1.31 m s-1 (8 kg steel) in the shallow depth ranges. Hydrodynamically shaped steel weights weighing 5 kg would be an appropriate substitute for 8.5 kg rock weights irrespective of fishing method.

Seabird bycatch in the Argentinean demersal longline fishery, 2001−2010

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Jan 2013

Seabird mortality associated with fisheries is one of the major threats leading to population decreases of certain species, particularly albatrosses and petrels. The present study was conducted to (1) analyze seabird bycatch in the Argentinean demersal longline fishery during the decade 2001 to 2010, (2) provide a baseline of the levels of incidental mortality prior to the implementation of the National Plan of Action-Seabirds, and (3) characterize in space and time the occurrence and intensity of seabird mortality. Fishing effort decreased from some 30 million to 5 million hooks set per year, and the overall bycatch rate for the whole period was 0.033 (0.019 SE) birds per 1000 hooks. The estimated total mortality for the 10 yr period was 7470 ± 2449 seabirds, the majority being black-browed albatrosses and white-chinned petrels. Seabird mortalities decreased by 1 order of magnitude towards the end of the decade, not due to lower bycatch rates but to a drop in the number of hooks set per year. The progress achieved so far in Argentina is important, but if seabird bycatch is to be reduced to negligible levels, it is imperative that the National Plan of Action-Seabirds is effectively implemented and that the longline fishery comply with the conservation measure calling for the use of mitigation methods that came into effect in 2010. Other management-related actions, such as the increase of capacities within the National Observer Program and the refinement of seabird sampling protocols, will have an effect not only in the longline but also in the large trawl fishery, where seabird bycatch has also been documented.

¿cuántos albatros de ceja negra, Thalassarche melanophrys (Temminck, 1828) anidan en Chile?

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Jan 2008

Seabird mortality in the Patagonian toothfish longline fishery around Crozet and Kerguelen Islands, 2001-2003

Article

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Jan 2005
CCAMLR SCI

The legal Patagonian toothfish (Dissostichus eleginoides) longline fishery operating in the French Exclusive Economic Zones (EEZs) of Crozet and Kerguelen Islands (Subarea 58.6 and Division 58.5.1 respectively) killed 26 668 seabirds between September 2001 and August 2003. Overall, the white-chinned petrel (Procellaria aequinoctialis) was the most frequently killed species, with males being more frequently caught than females. Grey petrels (Procellaria cinerea) were caught accidentally in large numbers over this same period. Giant petrels (Macronectes spp.), black-browed albatrosses (Diomedea melanophrys) and grey-headed albatrosses (D. chrysostoma) were also caught over this period. A multivariate analysis suggests that a combination of factors (environmental and relating to fishing techniques) have an effect on the observed numbers of seabirds caught incidentally. The results of this study suggest that a significant part of the mortality of white-chinned petrels and grey petrels is explained by the time of year, geographical area and type of longliner (manual versus automatic baiting). Almost all of the incidental mortality occurred exclusively during the breeding season, except for giant petrels. The highest mortality of white-chinned petrels, grey petrels, black-browed albatrosses and grey-headed albatrosses corresponded to the chick-rearing period. In addition, the vessels using automatic baited longlines caught many more birds than those using manual baited longlines. Based on the results of this analysis, several recommendations are made with the aim of reducing the incidental mortality of the various species concerned in the French EEZs of Crozet and Kerguelen Islands (Subarea 58.6 and Division 58.5.1 respectively).

Cephalopods and mesoscale oceanography at the Antarctic Polar Front: Satellite tracked predators locate pelagic trophic interactions

Article

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Jun 1996

Predator data and exploratory fishing in the Scotia Sea have revealed the presence of cephalopod stocks in the Antarctic Polar Frontal Zone (PFZ). This is a vast, remote region where large epipelagic cephalopods aggregate into highly mobile schools making them difficult to locate and sample. We used satellite tagged predators and shipboard acoustics for coarse and fine scale location of cephalopod concentrations, and sampled them with commercial and scientific nets to determine the relationship between cephalopod distribution and mesoscale oceanographic features at the PFZ. Satellite tags were attached to 9 grey-headed albatrosses Diomedea chrysostoma, breeding at Bird Island, South Georgia, to monitor foraging at sea in January-March 1994. A foraging area at the PFZ, north of South Georgia, was located, an acoustic survey undertaken and a fixed station established where acoustic targets were found. A net survey was carried out with a commercial pelagic trawl, a rectangular midwater trawl 25 m(2) (RMT25), a horizontal multiple plankton sampler and a neuston net. Acoustic layers were targeted and the RMT25 sampled 200 m layers to 1000 m in daylight and darkness. Cephalopods were simultaneously recovered from food samples fed to D. chrysostoma chicks at Bird Island. Two CTD transects, approximately normal to the major current flow, were undertaken across the PFZ and remote-sensed sea-surface temperature images from NOAA polar orbiting satellites were obtained aboard ship. The pelagic trawl sampled a cephalopod community that closely resembled that exploited by D. chrysostoma. The largest and most conspicuous species was the ommastrephid squid Martialia hyadesi which is the most important cephalopod prey species. Net-sampled M. hyadesi had been feeding on crustaceans and mesopelagic fish. The cephalopod community was sampled in a feature, interpreted as a warm core ring, in an area characterised by mesoscale features associated with the bathymetry of the northern end of the Northeast Georgia Rise and near a gap in the Falkland Ridge. The association of these mesoscale features with the bathymetry suggests that they may be predictable foraging locations for the cephalopods and their predators.

Significant conservation benefits obtanained from the use of a new fishing gear in the Chilean Patagonian Toothfish fishery

Article

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Aug 2008
CCAMLR SCI

A new fishing technique, adapted from the artisanal trotline fishery for Patagonian toothfish ( Dissostichus eleginoides) in Chile is described. The modified artisanal system, which includes a net sleeve that is placed on secondary vertical lines, has practically eliminated depredation of fish by killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus). The performance of this fishing technique with regard to seabird mortality . The performance of this fishing technique with regard to seabird mortality and depredation by sperm and killer whales on fish catch rate was assessed during September-December 2006. The results were then compared with similar data obtained in 2002 in the same fleet in the same fishing grounds prior to the implementation of the modification. The number of seabirds killed in 2002 was 1 542 compared to zero in 2006; there was also a reduction in depredation of the catch from a maximum of 5% in 2002 to a maximum of 0.36% of the total catch in 2006. The fishers who developed the net sleeve modification called it 'cachalotera' (from 'cachalote' meaning sperm whale in Spanish). The term 'Chilean longline' is preferred in this paper because it was developed in 2005 in the Chilean toothfish fishery in the Magellan region.

Seabird use of discards and incidental captures at the Argentine hake trawl fishery in the Golfo San Jorge, Argentina

Article

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Jul 2006

We studied discard use and incidental mortality of seabirds attracted to high-sea trawl vessels operating in the Golfo San Jorge, Argentina, during the height of the fishing season in 2003 and 2004. Fourteen seabird species ate food made available by fishing operations. The most frequent and abundant seabirds (percent occurrence, mean number per haul) were the kelp gull Larus dominicanus (98.9%, 207.0), the black-browed albatross Thalassarche melanophrys (98.9%, 94.2) and the white-chinned petrel Procellaria aequinoctialis (91%, 8.4). Flock sizes for the 3 species var- ied from a few to a maximum of 1600 birds. Total seabird abundance varied significantly between stages of the fishing operation, being higher during discarding and haulback than during towing. Incidental capture of seabirds in nets was recorded in 37% of 89 hauls, with a mean capture rate of 1.2 birds per haul. Species incidentally caught were the great shearwater Puffinus gravis, the imper- ial cormorant Phalacrocorax atriceps and the Magellanic penguin Spheniscus magellanicus, with rates that varied between months and years. Considering the fishery's fishing effort, the estimated total numbers of birds killed during the study were 2254 great shearwaters (CV = 1.1), 1233 imperial cormorants (CV = 1.1) and 35 Magellanic penguins (CV = 2.4) in 2003, and 311 imperial cormorants (CV = 1.7) and 1516 Magellanic penguins (CV = 1.1) in 2004. Black-browed albatrosses and kelp gulls were also struck by the warp cable while feeding on discards from the surface, and drowned when they were dragged underwater. The results obtained in this study show that the hake trawl fishery operating in the Golfo San Jorge may have a significant effect on some seabird populations through the provision of fishing discards and incidental mortality.

Diet of grey-headed albatrosses at the Diego Ramirez Islands, Chile: Ecological implications

Article

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Aug 2004
ANTARCT SCI

The diet of grey-headed albatrosses at Diego Ramírez was analysed and compared to that of the sympatric black-browed albatross. Diet composition was inferred from an analysis of prey hard parts present in 103 chick regurgitates obtained during breeding seasons 2000, 2001 and 2002. The squid Martialia hyadesi predominated in the diet samples in 2001 and 2002 (89% and 81% of reconstituted mass), but was absent from the 2000 samples. Reconstituted mean mass per sample in 2000 was significantly lower than in 2001 and 2002. Chick growth rate during 2000 was also the lowest recorded. This suggests that M. hyadesi plays an important role in the breeding performance of grey-headed albatrosses at Diego Ramírez. Low presence of M. hyadesi in grey-headed albatrosses' diet at South Georgia in 2000, a year with significant low breeding success, suggests ocean-wide processes affecting the availability of this prey to both populations simultaneously. Overlap in diet composition, and inferred feeding areas, between the sympatric albatross species at Diego Ramírez was minimal. Grey-headed albatrosses fed mainly on species associated with the Antarctic Polar Front, whereas black-browed albatrosses consumed benthopelagic species frequently caught in fishing operations in southern Chile.

Seabird mortality in the Patagonian toothfish longline fishery around the Prince Edward Islands, 1996–2000

Article

Full-text available

Jun 2002
ANTARCT SCI

Sanctioned longline fishing for Patagonian toothfish around the Prince Edward Islands (a globally important seabird breeding site) commenced in 1996 following high levels of Illegal, Unregulated and Unreported (IUU) fishing. Independent fishery observers accompanied all but two sanctioned trips between 1996 and 2000, allowing a thorough understanding of the impact of this fishery on seabirds. Overall, white-chinned petrels Procellaria aequinoctialis were by far the most frequently killed species. However, during the first year, when lines were set during the day and night, a significant number of albatrosses (particularly grey-headed albatrosses Thalassarche chrysostoma) were also killed. Birds were caught almost exclusively during their breeding seasons and most birds killed were breeding adult males from the Prince Edward Islands. Albatrosses and giant petrels were caught almost exclusively during day sets, whereas catch rates of white-chinned petrels did not differ between day and night sets. Albatrosses were caught closer to the islands than white-chinned petrels. Most white-chinned petrel carcasses were hooked in their wings and bodies, whereas albatrosses were caught most frequently in their bills and contained large numbers of baits. Rates of seabird bycatch in the sanctioned fishery decreased from 0.19 birds per 1000 hooks to 0.034 birds per 1000 hooks during the time of this study. This was probably mainly due to stricter implementation of mitigation measures and a progressive movement farther away from the islands over the years. We estimate that the combined impact of legal and IUU longline fishing around the Prince Edward Islands over the past four years could have resulted in between 7000 and 17 000 seabird mortalities and could have had significant impacts on the breeding populations of several seabird species breeding on the Prince Edward Islands. This was mainly due to high levels of IUU fishing during 1996/97.

The status of Black‐browed Albatrosses Thalassarche melanophrys at Diego de Almagro Island, Chile

Article

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Jul 2003
IBIS

Seabird mortality Falkland Islands and beyond

Article

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Sep 2006
BIOL CONSERV

Specifically tasked seabird observers were placed onboard demersal (bottom) finfish trawlers operating in the Falkland Islands in 2002/2003 to investigate the level of seabird mortality caused by the fleet. The observers were tasked to record seabird interactions during shooting, trawling and hauling operations during 157 days of coverage. It is estimated that >1500 seabirds, predominantly Black-browed albatross (Thalassarche melanophris), were killed by finfish trawlers during this period. Significant levels of mortality were also recorded on the Patagonian Shelf, north of the islands. Birds were killed after being dragged underwater by the warp cable while feeding on factory discharge at the stern of the vessel. An unknown proportion of these birds slide down the cable and become impaled on a splice in the cable, which was situated on average at 90 ± 40 m from the waters surface, and are subsequently hauled onboard. The incidence of mortality caused by the many large trawling fleets around the world that discharge factory waste and attract large bodied seabirds (e.g. albatross and large petrels) requires immediate investigation.

Factors affecting the number and mortality of seabirds attending trawlers and long-liners in the Kerguelen area

Article

Full-text available

Jan 2000

The factors affecting the number and the mortality rates of seabirds attending long-liners and trawlers fishing in the Kerguelen area were studied during four successive seasons (1994–1997), based on observations carried out onboard by dedicated observers. Twenty-four species of seabirds were observed attending fishing vessels, representing an average of 591 birds/census. The total numbers attending varied mainly according to the year, the cloud cover and the presence of offal from long-liners. The dumping of offal increased the numbers of birds attending the vessel, especially when the offal could be easily handled by birds. The activity of the vessels also affected the numbers attending, birds being more abundant during line setting and trawl hauling. White-chinned petrels were the most abundant ship-following seabirds, followed by black-browed albatrosses, giant petrels and cape petrels. The number of white-chinned petrels, black-browed and grey-headed albatrosses attending fishing vessels increased in the time between spring and autumn, whereas it was the reverse situation for giant petrels and cape petrels. Four species of seabirds were caught by fishing gear, mainly by long-lines: white-chinned petrels, and black-browed, grey-headed and wandering albatrosses. Taking into account the number of birds from each species attending long-liners and known to be potential by-catch, some species appear to be more susceptible to being caught than others. White-chinned and grey-headed albatrosses are caught in much higher proportions than the numbers present, whereas black-browed albatrosses are caught in lower numbers. Giant petrels are abundant around long-liners but were never caught. In long-liners, most birds were killed when the lines were set during the day or when the deployment of the scaring device was not successful, with an overall figure of 0.47 birds/1000 hooks. Only one albatross was caught when the lines were set during the night. White-chinned petrels represented 92.2% of all birds killed by long-liners. The number of birds caught varied significantly among months and among years. The type of bait used also affected the catch rate. The catch rate was related to the number of birds attending the long-liner only for black-browed albatrosses. Most birds killed by trawlers were entangled by the netsonde cable. The efficiency of mitigation measures in order to reduce seabird mortality is discussed and it is stressed that night setting is the most efficient way to reduce mortality and should be enforced everywhere when possible. However, further methods should be developed to reduce the mortality of species active at night, especially white-chinned petrels whose populations in the Indian Ocean may by threatened by long-line fisheries.

Comparison of census methods for black-browed albatrosses breeding at the Ildefonso Archipelago, Chile

Article

Full-text available

Apr 2008

A breeding population of black-browed albatrosses has been known to exist at the Ildefonso Archipelago, Chile, for >90years but the population has never been censused using scientifically defendable methods. To estimate population size, and examine the accuracy and practicality of various census methods, the population was censused in the 2002/2003 breeding season using (a) ground-truthed aerial photography, (b) yacht-based photography, (c) ground counts, (d) quadrat sampling and (e) point-distance sampling. Compared to ground-truthed aerial photography (judged the most accurate) yacht-based photography underestimated population size by 55%, ground counts by 13%, quadrat sampling by 11% and point-distance sampling by 9%. Ground-truthed air photography revealed that in the 2002/2003 breeding season 47,000 pairs of black-browed albatrosses bred at the Ildefonso Archipelago. A repeat aerial census in 2006 suggested the size of the breeding population had not changed in the 4years between the two censuses. After the Falkland Islands/Islas Malvinas, South Georgia and Diego Ramirez, the Ildefonso Archipelago holds the fourth largest population of black-browed albatrosses in the world.

Mitigation of seabird mortality on factory trawlers: Trials of three devices to reduce warp cable strikes

Article

Full-text available

Aug 2006

Experimental trials were conducted onboard a stern trawler to identify the relative efficacy of three emerging mitigation measures (tori lines, warp scarer and Brady baffler) designed to reduce seabird mortality caused by warp cable strikes. The use of mitigation measures was clearly shown to substantially reduce seabird mortalities from collisions between seabirds and warp cables. Based on an established significant relationship between contact rate and seabird mortality, when using contact rate as an index of mortality there was a clear performance hierarchy of the three measures. Tori lines and the warp scarer were significantly more effective at reducing contacts than the Brady Baffler, whilst tori lines represent a smaller, but still significant, improvement on the warp scarer. While further testing would be required under local environmental and operational conditions, our findings are likely to have application for many trawl fisheries around the world.

Status and distribution of wandering, black-browed and grey-headed albatrosses breeding at South Georgia

Article

Full-text available

Aug 2006

Long-term studies at Bird Island, South Georgia, show that numbers of wandering, black-browed and grey-headed albatrosses have been decreasing since the late 1970s. To determine the status of the total South Georgia population, all known colonies were censused in 2003/2004 using a combination of yacht-based digital photography and ground counts. The breeding population estimates from this census are 1,553 pairs of wandering albatross, 74,296 pairs of black-browed albatross and 47,674 pairs of grey-headed albatross. A 30% decline since 1984 was recorded for wandering albatross, and comparison of a sample of black-browed and grey-headed albatross colonies on the mainland of South Georgia photo-censused in both 1985/1986 and 2003/2004 indicates similarly substantial population declines. Unless these decreases can be halted or reversed, doubt will exist as to the long-term viability of these species of albatross at South Georgia.

Assessing the impact of the pelagic longline fishery on Albatrosses and Petrels in the Southwest Atlantic

Article

Full-text available

May 2010
AQUAT LIVING RESOUR

The black-browed (Thalassarche melanophrys) and Atlantic yellow-nosed (Thalassarche chlororhynchos) albatrosses and the white-chinned petrel (Procellaria aequinoctialis) are the seabird species most frequently captured by pelagic longline fisheries in the southwest Atlantic. This study estimates this type of bycatch and describes the spatial-temporal patterns of the incidental capture of these species by the Uruguayan pelagic longline fleet, based on data collected by scientific observers on 47 fishing trips from 2004 to 2007. Three generalized linear models (GLM) models were employed to predict bycatch for each species based on the observed data. We also developed a spatio-temporal species-specific analysis. Captures were recorded in Uruguayan waters, mainly over the slope and depth waters, and in international waters adjacent to Uruguay, the north of Argentina, and the south of Brazil. The highest catch rates for black-browed albatrosses and white-chinned petrels were recorded on the Uruguayan slope from fall to spring, while the highest values for Atlantic yellow-nosed albatrosses were recorded further to the north, in the international waters off Brazil in late winter. The average estimated number of black-browed and Atlantic yellow-nosed albatrosses and white-chinned petrels caught during the study period was 1683, 257 and 239 birds, respectively. Taking into account the total effort of the fleet, these values represent an estimated catch rate of 0.276, 0.042, and 0.039 birds/1000 hooks for these species, respectively. The results of the present study suggest that the annual impact of this fishery is medium to high on the black-browed albatross, low on the Atlantic yellow-nosed albatross and low on the white-chinned petrel. However, the situation of these species in the southwest Atlantic should be viewed with considerable concern, as our understanding of the impact of the bycatch on their populations requires more research. Any effort to reduce seabird mortality in the southern hemisphere should target this geographic region.

Global Circumnavigations: Tracking Year-Round Ranges of Nonbreeding Albatrosses

Article

Full-text available

Feb 2005
SCIENCE

Although albatrosses are paradigms of oceanic specialization, their foraging areas and migration routes when not breeding remain essentially unknown. Our continuous remote tracking of 22 adult gray-headed albatrosses for over 30 bird-years reveals three distinct strategies: (i) Stay in breeding home range; (ii) make return migrations to a specific area of the southwest Indian Ocean; and (iii) make one or more global circumnavigations (the fastest in just 46 days). The consistencies in patterns, routes, and timings offer the first hope of identifying areas of critical habitat for nonbreeding albatrosses, wherein appropriate management of longline fisheries might alleviate the plight of the world's most threatened family of birds.

Population changes in albatrosses at South Georgia

Article

Jan 1998

Experimental evaluation of the effectiveness of weighting regimes in reducing seabird by-catch in the longline toothfish fishery around South Georgia

Article

Jan 2000
CCAMLR SCI

A series of experiments was carried out in February 1999 at South Georgia (Subarea 48.3) to examine the effects of different weighting regimes on the incidental mortality of birds caught on longlines fishing for toothfish (Dissostichus spp.). Three regimes were examined, with weights of 4.25, 8.5 and 12.75 kg attached at 40 m intervals on a Spanish-rigged longline. There was a significant reduction in bird mortality when 8.5 kg was used compared to 4.25 kg, but no further significant reduction when 12.75 kg was used. Therefore to minimise seabird by-catch, line-weighting regimes of at least 8.5 kg at 40 m intervals should be used. Results suggested that seabird by-catch on lines using effective weighting regimes may be even further reduced where all lines being set in the vicinity use effective line-weighting regimes. The importance of a good design in experiments of this type is emphasised, because even though conditions may be held as constant as possible within experiments, the ability to separate treatment effects from other sources of variation (e.g, environmental factors) must be preserved.

Regional fisheries management organisations: Their duties and performance in reducing by-catch of albatrosses and other species

Article

Jan 2005

C.J. Small

Effect of line sink rate on albatross mortality in the Patagonian toothfish longline fishery

Article

Jan 2000
CCAMLR SCI

Graham Robertson

An experiment was conducted on autoline and Spanish-system longline vessels to derive a sink rate and line-weighting regime that would minimise the capture of albatrosses based on knowledge of line sink rates and albatross diving abilities. Sink rates of lines deployed into propeller turbulence, which tended to keep lines aloft, varied as a function of distance between line weights. Asymptotic sink rates (0.1-0.15 m/s) were achieved with 70 m intervals between 6.5 kg weights. Sink rates to 4 m depth were greatest with 35 m (0.44 m/s) and 50 m (0.33 m/s) between weights. For vessels using bird-scaring lines and setting lines in propeller turbulence, longline sink rates >0.3 m/s should greatly reduce the incidental take of albatrosses. For autoline vessels with gear and line-setting characteristics similar to the experimental vessel, this sink rate should be achievable with 4 kg weights distributed every 40 m on longlines.

Analysis of albatross and petrel distribution within the CCAMLR Convention Area: results from the Global Procellariiform Tracking Database

Article

Jan 2006
CCAMLR SCI

CCAMLR has implemented successful measures to reduce the incidental mortality of seabirds in most of the fisheries within its jurisdiction, and has done so through area- specific risk assessments linked to mandatory use of measures to reduce or eliminate incidental mortality, as well as through measures aimed at reducing illegal, unreported and unregulated (IUU) fishing. This paper presents an analysis of the distribution of albatrosses and petrels in the CCAMLR Convention Area to inform the CCAMLR risk- assessment process. Albatross and petrel distribution is analysed in terms of its division into FAO areas, subareas, divisions and subdivisions, based on remote-tracking data contributed to the Global Procellariiform Tracking Database by multiple data holders. The results highlight the importance of the Convention Area, particularly for breeding populations of wandering, grey-headed, light-mantled, black-browed and sooty albatross, and populations of northern and southern giant petrel, white-chinned petrel and short- tailed shearwater. Overall, the subareas with the highest proportion of albatross and petrel breeding distribution were Subareas 48.3 and 58.6, adjacent to the southwest Atlantic Ocean and southwest Indian Ocean, but albatross and petrel breeding ranges extend across the majority of the Convention Area. Subareas with the lowest proportion of breeding distribution were Subareas 88.2 and 88.3. The distribution data also emphasise the importance for breeding albatrosses and petrels of regions north of the CCAMLR boundaries, particularly including areas managed by CCSBT, ICCAT, IOTC and WCPFC. Priority gaps in current tracking data are identified, especially relating to studies of non- breeding distribution. These data will be essential for comprehensive assessment of risks of incidental mortality for albatrosses and petrels foraging in the Convention Area.

Tracking Ocean Wanderers: The Global Distribution of Albatrosses and Petrels

Article

Jan 2003

Diving Depths of White-Chinned Petrels

Article

Nov 1994

N. Huin

DIVING DEPTHS OF WHITE-CHINNED PETRELS'

Article

N Hum

For many seabirds, the ability to submerge to capture prey is a key adaptation for their foraging behavior. Studies of diving in seabirds have typically featured species known to be virtually dependent on long, often deep, dives for their livelihood, e.g., penguins (re-viewed in Croxall et al. 1993) alcids (reviewed in Bur-ger 199 1), cormorants (Wilson and Wilson 1988, Crox-all et al. 199 1, Wanless et al. 199 1). As far as the size of the birds has permitted, these studies have pro-ceeded from collecting data on maximum depth ofdive via multiple maximum depths to continuous records of diving depth against time and recently, in the larger penguins, with simultaneous collection of velocity and/ or locational data (Kooyman et al. 1992, Ancel et al. 1992). Although some members of the Procellariiformes and of other families of the Pelecaniformes (e.g., Su-lidae) have long been known as proficient divers (Ku-roda 1954, Ashmole 1971, Brown et al. 1978) only anecdotal information on the depths they attain has been available until very recently. The use of light-weight capillary gauges (Burger and Wilson 1988) has created opportunities to obtain reliable quantitative data on the maximum depth reached by a wide variety of seabirds, particularly penguins and alcids (Burger 1991) but also Cape Gaune& Sula capensis (.&%I& and Walter 1993). South Georaia Divina Petrels Pele-canoides georgick (Prince and Jones 1<92), and four species of albatross Diomedeidae (Prince et al. 1994). With the exception of the highly specialized Peleca-noididae, the Procellaridae (petrels and shearwaters) are the best adapted of the Procellariiformes for diving. Species in this family may dive as much as 20 m deep (Skim 1979). This paper reports the first systematic quantitative data on diving depths for any species of petrel.

Estimates of seabird incidental catch by pelagic longline fisheries in the South Atlantic Ocean

Article

Apr 2013
ANIM CONSERV

Read the Commentaries on this Feature Paper: Finding the missing pieces: working to solve the fisheries bycatch puzzle ; Next step for reducing seabird bycatch ; Requisite improvements to the estimation of seabird by‐catch in pelagic longline fisheries Response from the authors: Incidental catch of seabirds: strengthening observer programs and increasing cooperation

The effect of American and Spanish longline systems on target and non-target species in the eastern South Pacific swordfish fishery

Article

Jun 2009
FISH RES

Catch compositions obtained using two different types of commercial surface longlines for swordfish (Xiphias gladius) in the eastern South Pacific were compared. The American (“Florida style”) system uses polyamide monofilament nylon for the mainline and gangions, whereas the Spanish system consists of polyethylene multifilament with wire in the distal part of the gangion. A total of 37 fishing sets were carried out using both longline types. The amount and diversity of species caught, mainly swordfishes, billfishes, and tunas (Thunnus spp.), was highest with the monofilament longline; however, shark catches were higher with the multifilament longline. The type of longline significantly affected total catch, swordfish catches, and shark catches; total catch and swordfish catch rates were higher with the monofilament longline and shark catch rates higher with the multifilament longline. Moreover, a positive correlation was found between total and swordfish catch rates and the soak time with the monofilament longline, and between shark catch rates and the soak time with the multifilament longline. Significant differences were found in the average length of blue sharks according to the type of fishing gear used: larger specimens were caught on the multifilament longlines. A selectivity effect was also observed, with the multifilament system retaining more specimens exceeding 200cm in fork length. Generalized additive models were developed to explain swordfish, shark, and teleost catches as a function of seven operational (longline system, soak time, depth, number of light-sticks), spatial (zone), and environmental (sea surface temperature, wind velocity) variables. The final fits of the models explained 68% of the swordfish catches, 38% of the shark catches, and 81% of the teleost catches. The results showed that two operational variables – longline system, soak time – were best able to explain the catches in all the models. The effect of the environmental variables significantly explained swordfish and teleost catches, whereas only wind velocity significantly added to the sharks model. These results show that the use of monofilament leaders in the surface longlines might be an effective way to reduce shark by-catches in the eastern South Pacific swordfish fishery.

Diving Depths of albatrosses

Article

Sep 1994
ANTARCT SCI

Studies of diving in seabirds have mainly been confined to penguins, alcids and cormorants. There are few data on the depths to which other seabirds dive although some species are known to have considerable abilities for diving and swimming underwater e.g. shearwaters (Kuroda 1954, Brown et al. 1978), diving petrels (Prince & Jones 1992) and gannets (Adams & Walter 1993).

An estimate of the population sizes of Black-browed ( Thalassarche melanophrys ) and Grey-headed ( T. chrysostoma ) Albatrosses breeding in the Diego Ramírez Archipelago, Chile

Article

Sep 2007

The Diego Ramírez Archipelago, Chile, is the southernmost albatross breeding ground in the world and holds globally important numbers of Black-browed (Thalassarche melanophrys) and Grey-headed (T. chrysostoma) Albatrosses. A census in the Diego Ramírez Archipelago has been attempted only once, in 1980-81, with methods that were unlikely to determine population sizes accurately. The number of breeding pairs of both species was estimated in the incubation period of 2002 using a combination of aerial photography, ground-based photography, yacht-based photography and ground counts. All islands in the archipelago were surveyed. There were an estimated 55 000 pairs of Black-browed and 17 000 pairs of Grey-headed Albatrosses breeding at the archipelago. Based on the results of this census, and those for the other four known breeding locations, the populations of both species of albatrosses in Chile are considerably larger than previously reported, comprising ∼20% of the Black-browed Albatrosses and 23% of Grey-headed Albatrosses in the world, with the largest populations of both species occurring in the Diego Ramírez Archipelago.

Utilization of offal and discards from “finfish” trawlers around the Falkland Islands by the Black‐browed Albatross Diomedea melanophris

Article

Apr 2008
IBIS

Multinational fisheries operating in the vicinity of the Falkland Islands currently take c. 90,000 tonnes of true fish (“finfish” as opposed to squid) per annum, including hakes Merluccius spp., Southern Blue Whiting Micromesistius australis, Hoki Macruronus magel-lanicus and Red Cod Salilota australis, and generate substantial quantities of fisheries waste in the form of discards and offal. This paper examines the use made of this waste by scavenging Black-browed Albatrosses Diomedea melanophris which breed in the Falklands. The various types of waste produced are described and their consumption by scavenging albatrosses is quantified. The results indicate that Black-browed Albatrosses obtain c. 8000 tonnes of food per annum from this source, of which two-thirds is offal and the remainder whole discards. The energy content of this waste is equivalent to 4.4% of the estimated total annual energy requirements of the Falklands Black-browed Albatross population. However, as the fishery is a greater predator of finfish stocks than are the albatrosses, its long-term impact may be detrimental to these birds.

Preferred foraging areas of Heard Island albatrosses during chick raising and implications for the management of incidental mortality in fisheries

Article

May 2008
AQUAT CONSERV

Incidental mortality in fisheries is causing declines in many albatross populations around the world. To assess potential interactions with regional fisheries satellite tags were used to track black‐browed albatrosses ( Thalassarche melanophrys ) and light‐mantled sooty albatrosses ( Phoebetria palpebrata ) breeding on Heard Island during the chick‐rearing periods of 2003/04. This was the first time individuals from either population had been tracked. Black‐browed albatrosses foraged largely within the Heard and McDonald Islands Economic Exclusion Zone (EEZ) north‐east of the island, although 20% of foraging trips were to areas north of the EEZ into Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) areas 58.5.1 and 58.5.2 and into the Îles Kerguelen EEZ. In contrast, the light‐mantled sooty albatrosses foraged well south of Heard Island along the southern boundary of the Antarctic Circumpolar Current. Both species appear to face minimal risk of incidental mortality during the chick‐rearing period in the regulated, legal fisheries, but are threatened by illegal, unreported and unregulated (IUU) fishing vessels operating in the southern Indian Ocean. Copyright © 2007 John Wiley & Sons, Ltd.

Breeding frequency in Grey‐headed Albatrosses Thalassarche chrysostoma

Article

Sep 2006
IBIS

Although Grey-headed Albatrosses Thalassarche chrysostoma are usually regarded as biennial breeders, taking a year off following a successful breeding attempt, a small proportion of successful birds attempt to breed annually. This proportion was higher at Marion Island (5.4%) than at Bird Island, South Georgia (1.0%), suggesting that conditions are more favourable at Marion Island. This hypothesis is supported by higher average breeding success and shorter lags following both successful and failed breeding attempts at Marion Island. Factors favouring reproduction at Marion Island may include reduced intraspecific competition (given the much smaller breeding population) and/or more predictable food supply (owing to production of meso-scale eddies associated with the Indian Ocean Ridge). Although annual breeding appeared to increase the risk of adult mortality, with several birds that attempted to breed annually found dead the following year, at least some birds greatly enhanced their reproductive output, with one male raising five chicks in five successive years. Contrary to life-history theory, there was no evidence that older birds were more likely to attempt annual breeding because of declining reproductive value.

Artisanal longline fisheries in Southern Chile: Lessons to be learned to avoid incidental seabird mortality

Article

Jan 2006
BIOL CONSERV

Industrial longline fisheries are considered worldwide as the main threat to albatross and petrel populations, particularly at open oceans. However, inside countries’ EEZ artisanal fleets account for a significant fishing effort and eventually, could represent a major threat to these species than industrial fishing. Here we provide the first assessment of incidental mortality in two artisanal fleets in southern Chile, targeting Austral hake and Patagonian toothfish, which accounts for 0.9 and 20 millions hooks/year, respectively. Fishing techniques of these fleets have many particularities that made their operation markedly different from the more known industrial longliners, therefore their characteristics and sink rates are thoroughly described. By-catch rates (BPUE) estimated were low: 0.030 and 0.047 birds per 1000 hooks in hake and toothfish fisheries, respectively, despite that no mitigation measured was in use. These low results may reflect the fast sink rate profile of the particular longline type used by these fisheries, although the low abundance of species present may influence too. Both fleets use a modified longline having secondary hook-lines placed vertical along the mother line, each having a weight that increases significantly its sink rate, reaching 0.33 and 0.69–0.22 m s−1 in the hake and toothfish longlines, respectively. Considering the big fishing effort deployed by the artisanal toothfish fleet, recommendations on mitigation measures are given for each fishery to further improve their fishing techniques.

Movements and foraging areas of na??ve, recently weaned southern elephant seal pups

Article

Mar 2002
J ANIM ECOL

Female southern elephant seals ( Mirounga leonina L . ) expend variable, often large, amounts of their stored body resources on their pups during lactation. There is some evidence that pups with higher weaning masses have a better chance of surviving their first year. But in order to understand what level of maternal investment is required to produce successful pups, we need to understand the behaviour and problems faced by naïve pups before nutritional independence. We used satellite telemetry to track 30 newly weaned pups on their first trip to sea from their natal site at Macquarie Island in 1995 and 1996. Track duration varied from 2 to 179 (mean, 77) days. Seven seals were tracked for the entire duration of their first trip. The movements were grouped into three phases. Phase 1 (mean duration 30 days) was characterized by rapid and directed dispersal from Macquarie Island at daily travel rates of up to 140 km day ⁻¹ . Phase 2 (mean duration 67 days) consisted of slower travel rates (generally < 20 km day ⁻¹ ) where activity was often centred on localized patches up to 1900 km from Macquarie Island. This phase was sometimes interrupted by bouts of increased travel rate as the seal moved to another patch. Phase 3 (mean duration 42 days) consisted of prolonged increased travel rates as the seals returned to Macquarie or, in one case, Chatham Island. The routes of the tracks to the south‐east were very similar. Simulated tracks based on a constant heading of magnetic east, at variable swimming speed, and modified by ocean current vectors produced a pattern similar to, but not identical to, the south‐east tracks. The tracks to the west and south were more diverse and meandering. Based on a nearest neighbour analysis, neither sex, year nor weaning mass influenced Phase 1–2 or Phase 2–3 transition locations. Phase 2 tracks were associated in the south‐eastern group with the Pacific Antarctic Ridge and in the south‐west group, to a lesser extent, with the Indian Antarctic Ridge. The southern limits of Phase 2 tracks in the south‐eastern group aligned with the southern Antarctic Circumpolar Circulation front. Using calculated estimates of body composition at weaning and estimates of the rate of utilization of body reserves for the period before animals reach phase 2 of their trip, we estimate that large pups will have reserves remaining to supply their needs whereas pups in the small group are approaching critical limits. However, these estimates are based on several assumptions and extrapolations. More information on body composition of pups at weaning and departure is needed along with behavioural information to clarify the value of maternal expenditure in terms of offspring survival.

The Analysis of Designed Experiments and Longitudinal Data by Using Smoothing Splines

Article

Aug 1999
J R STAT SOC C-APPL

In designed experiments and in particular longitudinal studies, the aim may be to assess the effect of a quantitative variable such as time on treatment effects. Modelling treatment effects can be complex in the presence of other sources of variation. Three examples are presented to illustrate an approach to analysis in such cases. The first example is a longitudinal experiment on the growth of cows under a factorial treatment structure where serial correlation and variance heterogeneity complicate the analysis. The second example involves the calibration of optical density and the concentration of a protein DNase in the presence of sampling variation and variance heterogeneity. The final example is a multienvironment agricultural field experiment in which a yield–seeding rate relationship is required for several varieties of lupins. Spatial variation within environments, heterogeneity between environments and variation between varieties all need to be incorporated in the analysis. In this paper, the cubic smoothing spline is used in conjunction with fixed and random effects, random coefficients and variance modelling to provide simultaneous modelling of trends and covariance structure. The key result that allows coherent and flexible empirical model building in complex situations is the linear mixed model representation of the cubic smoothing spline. An extension is proposed in which trend is partitioned into smooth and non-smooth components. Estimation and inference, the analysis of the three examples and a discussion of extensions and unresolved issues are also presented.

The Evangelistas Islets, Chile: A new breeding site for black-browed albatrosses

Article

Oct 2003

A previously undescribed population of black-browed albatrosses (Thalassarche melanophrys) is reported at the Evangelistas Islets, Straits of Magellan, Chile. The population was censused from aerial photographs taken on 13 October 2002 that yielded an estimate of the number of breeding pairs. A combined total of 4,670 pairs of black-browed albatrosses were found nesting at Elcano and Lobos Islets, 2 of the 4 islets in the Evangelistas group. This new record raises to four the number of breeding islands of this albatross species in Chile.

The diet of black-browed albatrosses at the Diego Ramirez Islands, Chile

Article

Sep 2003
POLAR BIOL

The diet of black-browed albatrosses was studied at Gonzalo Island, Diego Ramirez, Chile, during the early chick-rearing periods of 2000, 2001, and 2002. Diet composition was determined by sampling chick-stomach contents during January and February of each year. Reconstituted meal mass was similar throughout the study, with diet being dominated by fish in all 3years. Overall, the main items taken were the fishes Macruronus magellanicus (66–89% by mass) and Micromesistius australis (2.6–3.7% by mass), which are both fisheries-related species, and the squid Martialia hyadesi (8–20% by mass). The distribution of the prey species indicates that black-browed albatrosses obtained the bulk of their food over the South American continental shelf, but also foraged at the Antarctic Polar Front. The prevalence in the diet of fish species discarded from fishing operations, and the presence of fish hooks and fish bait species, indicate a strong association with fisheries in southern Chile.

Demographic parameters of black-browed albatrosses Thalassarche melanophris from the Falkland Islands

Article

Aug 2011

Black-browed albatrosses Thalassarche melanophris are currently classified as globally endangered. The most important populations of this species are believed to be declining due to, amongst other factors, unsustainable levels of incidental mortality in fishing gear. However, detailed demographic data are lacking for several critical populations, including the largest of all, nesting in the Falkland Islands. Here, we present data from the first Falkland Islands detailed demographic study (at New Island) and show that, from 2003 to 2009, the mean adult survival probability was 0.942 (95% CI: 0.930–0.952). Nesting frequency of adults is amongst the highest recorded for Thalassarche albatrosses and breeding success (0.564 chicks per egg) is within normal values. The nesting population in the intensively studied plots experienced an increase of 4% per year from 2004 to 2009. These results indicate that the Falklands population may not be as threatened as previously supposed, although studies from more sites and a longer time series are needed to confirm or refute this. The high survival rates may partly reflect recent efforts to mitigate bycatch made by the Falkland Islands and other fisheries in the region. The reinforcement of such initiatives may be critical to buffer the black-browed albatross population against ecosystem shifts and natural disasters (such as harmful algal blooms) that will likely become more frequent with ongoing global changes. KeywordsNew Island–Bycatch–Demography–Red tide–Patagonian shelf

Respective impact of climate and fisheries on the growth of an albatross population

Article

Aug 2009

Climate and human activities such as fisheries impact many animal species. However, the demographic processes through which the population vital rates are affected, and the sensitivity of their growth rates, are poorly understood. The Black-browed Albatross, Thalassarche melanophrys, is a long-lived threatened seabird species. Previous studies have shown that the adult survival and breeding success of the population breeding at Kerguelen are affected by sea surface temperature anomalies (SSTA) during both the breeding and the nonbreeding season, and by tuna long-lining in Tasmanian waters through bycatch mortality. Here, using long-term demographic data from a Black-browed Albatross colony monitored for 26 years at Kerguelen, we estimate all demographic parameters from early to adult stages of the life cycle in order to build a fully parameterized population model and predict population growth rates under several scenarios of climate and fishing effort. The observed population growth rate (1.003) indicates that the population was stable or slightly increasing, and our population model gives a close estimate of 1.008. Population growth rate is more sensitive to survival of experienced breeders and accordingly to a change in SSTA during incubation and to tuna long-lining effort (both affecting survival of experienced breeders) than to other demographic parameters/environmental covariates. The population stability results from multiple factors and complex relationships between demographic parameters and environmental conditions, and therefore population equilibrium is precarious. If fishing effort remains stable at its current level and positive SSTA increase, or inversely if fishing effort decreases and SSTA remain similar to present values, then the population would increase. However, if fishing effort increases by 20% (i.e., to 40 million hooks) on the wintering grounds, without any change in SSTA, then the population would decrease at 0.9% per year. If fishing effort stops, the population would increase at 3.5% per year, suggesting that bycatch mortality probably currently limits the Black-browed Albatross population at Kerguelen. Our study shows how this type of model could be useful to predict trajectories of top predator populations, and eventually lower trophic web levels, in relation to climatic projections and future human activities. We highlight the need to reinforce mitigation measures.

Albatross Populations In Peril: A Population Trajectory For Black-Browed Albatrosses At South Georgia

Article

Mar 2006

Simulation modeling was used to reconstruct Black-browed Albatross (Diomedea melanophris) population trends. Close approximations to observed data were accomplished by annually varying survival rates, reproductive success, and probabilities of returning to breed given success in previous years. The temporal shift in annual values coincided with the start of longline fishing at South Georgia and potential changes in krill abundance. We used 23 years of demographic data from long-term studies of a breeding colony of this species at Bird Island, South Georgia, to validate our model. When we used annual parameter estimates for survival, reproductive success, and probabilities of returning to breed given success in previous years, our model trajectory closely followed the observed changes in breeding population size over time. Population growth rate was below replacement (lambda < 1) in most years and was most sensitive to changes in adult survival. This supports the recent IUCN uplisting of this species from "Vulnerable" to "Endangered." Comparison of pre-1988 and post-1988 demography (before and after the inception of a longline fishery in the breeding area) reveals a decrease in lambda from 0.963 to 0.910. A life table response experiment (LTRE) showed that this decline in lambda was caused mostly by declines in survival of adults. If 1988-1998 demographic rates are maintained, the model predicts a 98% chance of a population of fewer than 25 pairs within 78 years. For this population to recover to a status under which it could be "delisted," a 10% increase in survival of all age classes would be needed.

Black-browed albatross numbers in Chile increase in response to reduced mortality in fisheries

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