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A novel combination of methods identifies priority conservation areas for an endemic California Current seabird
Abstract
There are growing pressures on marine biodiversity. Seabirds in particular are one the most‐threatened groups. The black‐vented shearwater ( Puffinus opisthomelas ) is endemic to Mexican islands and the only shearwater living its entire life cycle in the California Current System, one of the most productive large marine ecosystems in the world. Marine Protected Areas (MPAs) in this region, however, were designed without consideration of accurate data on seabird distributions.
Here, 57 black‐vented shearwaters were GPS‐tracked from their main breeding colony (95% of the global population) over four seasons (2016–2019) to estimate their at‐sea distribution. Two methods were applied to identify priority conservation areas: the approach developed by BirdLife International to identify marine Important Bird and Biodiversity Areas and a method using expectation‐maximization binary clustering to identify core foraging areas.
One potential marine Important Bird and Biodiversity Area close to the breeding colony and five core foraging areas were identified. These priority conservation areas were largely beyond the bounds of the current MPA network in the region.
Our results detail opportunities for improving the implementation of conservation and management measures in the California Current System region with respect to seabirds. The approach of combining site identification methods can be applied to other seabird species for which high‐resolution tracking data are available and can help guide conservation action plans and MPA design.
... This approach has been used widely to identify mIBAs for seabirds (e.g. Soldatini et al. 2022, Carr et al. 2023, Correia et al. 2024, including penguins off the Antarctic Peninsula (Dias et al. 2018 ), and to assess the adequacy of marine protected areas (MPAs) for marine predators, including penguins, in the Southwest Atlantic Ocean (Handley et al. 2020 ). We used a 90% kernel utilization distribution contour (UD) to calculate foraging ranges (mIBA-UD90) following Börger et al. (2006) and a 54% UD to determine core foraging areas using optimal isopleth value selection (V ander W al and Rodgers 2012 ). ...
The African penguin population has declined precipitously in recent decades, and if current rates of decline persist, this species could become extinct in the wild by 2035. Resource extraction of small pelagic fish prey by the purse-seine fishery around African penguin breeding colonies has been identified as a demographically meaningful threat to African penguins. Consequently, long-term, effective no-take zones around breeding colonies have been endorsed by an expert panel of scientists constituted by the South African government. Here, we consider the six largest South African penguin colonies that currently hold 76% of the global population. We evaluate the adequacy of different no-take zone options using a trade-off mechanism recommended by the expert panel. For all six colonies except Bird Island, Algoa Bay, which is subject to the least fishing pressure, the current no-take zone delineations are assessed as having little benefit to the African penguin and little to no cost to the purse-seine fishery. Four of the six current no-take zones include ≤50% of the African penguins' core foraging areas. Alternative no-take zones that approximate a more balanced trade-off offer more impactful alternatives to the current fisheries restrictions. Given the urgent need to implement evidence-based conservation interventions for the endangered African penguin, we recommend the substitution of the current no-take zones with those proposed herein.
Divergence in reproductive timing, known as allochrony, is an evolutionary process that in some cases has led to sympatric speciation. However, the mechanisms that could drive the existence of allochrony (e.g., environmental variability), and the role of the ecological adaptations to different seasons in the process of speciation are less known. Further, considering that several allochronic species of birds are threatened, it is important to improve our understanding of their ecology and their management and protection. Our work assessed whether seasonal allochrony has led to phenotypic and ecological differentiation and identified the environmental factors favoring it in Northern storm-petrels (Hydrobatidae).
First, considering that a key aspect in the study of allochrony is a good understanding of the species’ phenology, we assessed breeding phenology using several approaches (e.g. nest monitorin or deployment of geolocators). This included an evaluation of whether brood patch scoring serves as a reliable method for describing phenology in allochronic populations. Second, to understand the role of body size in the seasonal adaptations to the environmental temperature, we assessed whether Bergmann’s rule was met across all allochronic species
and populations of Northern storm-petrels. Third, to assess the role of other ecological adaptations to the environment, we focused on two contrasting systems of allochronic storm petrels, whose genetic differentiation have been well stablished but there is little knowledge on their ecological differentiation. In the first system, comprising the spring-breeding (hot season) and autumn-breeding (cool season) populations of the Cape Verde storm-petrel (Hydrobates jabejabe), which breed in Cabo Verde within the Eastern Tropical Atlantic, minimal genetic differentiation exists between them. In the second system, the summerbreeding
Townsend’s storm-petrel (Hydrobates socorroensis) and the winter- breeding Ainley’s storm-petrel (Hydrobates cheimnomnestes), which breed in Guadalupe Island within the subtropical Mexican Pacific, allochrony has led to a relevant genetic differentiation and they are regarded as sister species. For both systems, we compared the spatial ecology using GPS (for the breeding season) and geolocators (for the non-breeding season), and trophic ecology using isotopes between the allochronic populations. Overall, we found a greater ecological differentiation between populations with a greater genetic differentiation than in those with little differentiation. That is, body size and all the explored axes of the ecological niche were more differentiated between allochronic populations in
Guadalupe than in Cabo Verde. Regarding factors promoting allochrony and differentiation between populations, we found that Guadalupe shows a more pronounced temporal variation in marine productivity and night length compared to Cabo Verde. This implies that differentiation is more likely to occur within highly seasonal systems, encompassing variables such as air temperature, night length and oceanic productivity. These conditions favour reproductive isolation between populations, thereby facilitating differentiation and, ultimately, speciation. In addition, our research revealed that individuals from the allochronic populations of Guadalupe visited previously unrecognized and primarily non-overlaping areas during both, the breeding and the non-breeding periods. This discovery brings new
challenges to the management of the waters between United States and México. Further research is needed in other allochronic organisms, such as mice and fishes, to ascertain whether phenotypic, ecological, physiological and genetic differentiation among allochronic populations co-vary with the intensity of the seasonality and the allochronic speciation process.
Biologging technology is rapidly advancing—scientists are obtaining data on movement and behaviour for a range of species, more accurately than ever before. With this information, it is possible to understand more about important areas and their connections across the open ocean including the high seas, beyond national jurisdictions. But an absence of a global governance framework has so far hindered a coordinated approach to conservation action on the high seas.
We showcase a candidate high seas MPA in the Northeast Atlantic identified primarily from seabird tracking data and being taken forward under a regional process: the North Atlantic Current and Evlanov Seamount (NACES) MPA, under the OSPAR Commission. It provides a unique case study to learn about the intricacies of implementation when applying tracking information for conservation. From this, we identify the facilitating conditions and challenges faced from identification to designation and highlight actionable opportunities for future area‐based management of the high seas that will be made possible under a new agreement.
Policy implications. The North Atlantic Current and Evlanov Seamount (NACES) MPA demonstrates the power of translating tracking data into usable geospatial knowledge to inform conservation and policy and provides an exemplar for a data‐driven approach to high seas conservation that can become a reality under the forthcoming governance framework (under the United Nations Convention on the Law of the Sea on the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction (known as the BBNJ Agreement)). This new agreement presents a unique conservation opportunity both for the application of tracking data to conservation outcomes and for the protection of migratory species.
Identifying important sites for biodiversity is vital for conservation and management. However, there is a lack of accessible, easily applied tools that enable practitioners to delineate important sites for highly mobile species using established criteria.
We introduce the R package ‘track2KBA’, a tool to identify important sites at the population level using tracking data from individual animals based on three key steps: (a) identifying individual core areas, (b) assessing population‐level representativeness of the sample and (c) quantifying spatial overlap among individuals and scaling up to the population.
We describe package functionality and exemplify its application using tracking data from three taxa in contrasting environments: a seal, a marine turtle and a migratory land bird.
This tool facilitates the delineation of sites of ecological relevance for diverse taxa and provides output useful for assessing their importance to a population or species, as in the Key Biodiversity Area (KBA) Standard. As such, ‘track2KBA’ can contribute directly to conservation planning at global and regional levels.
The conservation of migratory marine species, including pelagic seabirds, is challenging because their movements span vast distances frequently beyond national jurisdictions. Here, we aim to identify important aggregations of seabirds in the North Atlantic to inform ongoing regional conservation efforts. Using tracking, phenology, and population data, we mapped the abundance and diversity of 21 seabird species. This revealed a major hotspot associated with a discrete area of the subpolar frontal zone, used annually by 2.9–5 million seabirds from ≥56 colonies in the Atlantic: the first time this magnitude of seabird concentrations has been documented in the high seas. The hotspot is temporally stable and amenable to site‐based conservation and is under consideration as a marine protected area by the OSPAR Commission. Protection could help mitigate current and future threats facing species in the area. Overall, our approach provides an exemplar data‐driven pathway for future conservation efforts on the high seas.
Key Biodiversity Areas (KBAs) are sites that contribute significantly to the global persistence of biodiversity. The purpose of the Guidelines for using A Global Standard for the Identification of Key Biodiversity Areas is to ensure that KBA identification is based on consistent, scientifically rigorous yet practical methods. These KBA Guidelines provide an overview of the steps for identifying and delineating KBAs, together with explanation of how the KBA criteria, thresholds and delineation procedures should be applied in practice. The KBA Guidelines should be used hand-in-hand with the KBA Standard.
(The KBA Guidelines Ver. 1.1 is available here: https://portals.iucn.org/library/node/49131.)
Global threats to ocean biodiversity have generated a worldwide movement to take actions to improve conservation and management. Several international initiatives have recommended the adoption of marine protected areas (MPAs) in national and international waters. National governments and the Commission for the Conservation of Antarctic Marine Living Resources have successfully adopted multiple MPAs in the Southern Ocean despite the challenging nature of establishing MPAs in international waters. But are these MPAs representative of Southern Ocean biodiversity? Here we answer this question for both existing and proposed Antarctic MPAs, using benthic and pelagic regionalizations as a proxy for biodiversity. Currently about 11.98% of the Southern Ocean is protected in MPAs, with 4.61% being encompassed by no-take areas. While this is a relatively large proportion of protection when compared to other international waters, current Antarctic MPAs are not representative of the full range of benthic and pelagic ecoregions. Implementing additional protected areas, including those currently under negotiation, would encompass almost 22% of the Southern Ocean. It would also substantially improve representation with 17 benthic and pelagic ecoregions (out of 23 and 19, respectively) achieving at least 10% representation.
Aim
Marine protected areas can serve to regulate harvesting and conserve biodiversity. Within large multi‐use MPAs, it is often unclear to what degree critical sites of biodiversity are afforded protection against commercial activities. Addressing this issue is a prerequisite if we are to appropriately assess sites against conservation targets. We evaluated whether the management regime of a large MPA conserved sites (Key Biodiversity Areas, KBAs) supporting the global persistence of top marine predators.
Location
Southwest Atlantic Ocean.
Method
We collated population and tracking data (1,418 tracks) from 14 marine predator species (Procellariiformes, Sphenisciformes, Pinnipedia) that breed at South Georgia and the South Sandwich Islands, and identified hotspots for their conservation under the recently developed KBA framework. We then evaluated the spatiotemporal overlap of these sites and the different management regimes of krill, demersal longline and pelagic trawl fisheries operating within a large MPA, which was created with the intention to protect marine predator species.
Results
We identified 12 new global marine KBAs that are important for this community of top predators, both within and beyond the focal MPA. Only three species consistently used marine areas at a time when a potentially higher‐risk fishery was allowed to operate in that area, while other interactions between fisheries and our target species were mostly precluded by MPA management plans.
Main conclusions
We show that current fishery management measures within the MPA contribute to protecting top predators considered in this study and that resource harvesting within the MPA does not pose a major threat—under current climate conditions. Unregulated fisheries beyond the MPA, however, pose a likely threat to identified KBAs. Our approach demonstrates the utility of the KBA guidelines and multispecies tracking data to assess the contributing role of well‐designed MPAs in achieving local and internationally agreed conservation targets.
The Hutton's shearwater Puffinus huttoni is an endangered seabird endemic to Kaikōura, New Zealand, but the spatial and temporal aspects of its at‐sea foraging behavior are not well known.
To identify foraging areas and estimate trip durations, we deployed Global Positioning Systems (GPS) devices and Time‐Depth Recorders (TDR) on 26 adult Hutton's shearwaters during the chick‐rearing period in 2017 and 2018.
We found Hutton's shearwaters traveled much further from their breeding grounds at Kaikōura than previously considered, with most individuals foraging in coastal and oceanic areas 125–365 km south and near Banks Peninsula. Trip durations varied from 1 to 15 days (mean = 5 days), and total track lengths varied from 264 to 2,157 km (mean = 1092.9 km).
Although some diving occurred in near‐shore waters near the breeding colony, most foraging was concentrated in four regions south of Kaikōura. Dive durations averaged 23.2 s (range 8.1 to 71.3 s) and dive depths averaged 7.1 m (range 1.5 to 30 m). Foraging locations had higher chlorophyll a levels and shallower water depths than nonforaging locations. Birds did not feed at night, but tended to raft in areas with deeper water than foraging locations.
Mapping the spatial and temporal distribution of Hutton's shearwaters at sea will be fundamental to their conservation, as it can reveal potential areas of overlap with fisheries and other industrial users of the marine environment.
Understanding susceptibility of seabirds to fisheries bycatch requires quantifying overlap of seabird at-sea habitat with fisheries’ distribution and effort. Pink-footed Shearwaters (Ardenna creatopus) are vulnerable seabirds that breed only in Chile. Recently, high rates of Pink-footed Shearwater bycatch (i.e. >1,500 observed mortalities 2015–2017) were documented by observers in central Chilean purse-seine fisheries. We present analysis of Pink-footed Shearwater at-sea movements and overlap with central Chilean purse-seine fleets targeting common sardine (Strangomera bentincki), Peruvian anchoveta (Engraulis ringens), and Chilean jack mackerel (Trachurus murphyi). To determine overlap during 2015–2017, we paired locations from 49 Pink-footed Shearwaters rearing nestlings at Isla Mocha, Chile, with locations and number of observed purse-seine sets in central Chile. Pink-footed Shearwaters typically visited waters ≤30 km offshore throughout central Chile. Foraging trip durations varied interannually, with longer trips in 2016, but all years revealed persistent foraging hotspots near Valdivia, the Gulf of Arauco, and Isla Mocha, Chile. Greatest overlap between Pink-footed Shearwaters and fisheries occurred with the sardine/anchoveta fleet near Valdivia (artisanal and industrial) and the Gulf of Arauco (artisanal); overlap with the jack mackerel fleet was minimal. Given Pink-footed Shearwater bycatch documented in these fisheries, this overlap may indicate risk of bycatch for these birds, although we did not directly quantify shearwater–fisheries interaction. Our results can inform further fishery monitoring efforts, as well as collaboration among scientists, managers, and fishers to identify, quantify, and reduce fisheries bycatch of Pink-footed Shearwaters within Chile and internationally.
Outcome-based targets are needed to achieve biodiversity goals.
Estimating the population of burrow-nesting seabirds is a challenging task, as human presence in the colony creates disturbances and can damage burrows and occupants. Here, we present a novel method using aerial photographs taken with Unmanned Aerial Vehicles (UAVs) to estimate the population size of a burrow-nesting seabird, the Black-vented Shearwater (Puffinus opisthomelas), on Natividad Island, Mexico. Our results provide a census of burrows in the colony, with very low detection error (5.6%). This is greater accuracy compared to other methods based on extrapolating results from sample plots to total colony area. We then combined this burrow census with ground truth data on occupancy to estimate population size. We obtained a population estimate of 37,858 and 46,322 breeding pairs for 2016 and 2017 respectively. The proposed method provides a cost effective and repeatable approach for monitoring numbers of burrows occupied in a colony, thereby enabling easier and faster estimates of population trends. We suggest this method can be valid for other burrow-nesting species in habitats without dense vegetation cover.
The English Channel is one of the most anthropized marine ecosystems due to increasing human pressures, both along the coasts and at sea. Numerous marine protected areas (MPAs) have been created in this area but their ecological relevance still needs to be demonstrated for mobile species such as seabirds. Here, we identified the at-sea foraging and resting areas of black-legged kittiwakes to quantify their spatial overlap with existing neighbouring MPAs. Using solar-powered GPS-UHF, we tracked at-sea trips of 36 kittiwakes breeding at three colonies along the French coasts of the English Channel: Boulogne-sur-Mer (Hauts-de-France, n = 11), Fécamp (Normandy, n = 14) and Saint-Pierre-du-Mont (Normandy, n = 11). While kittiwakes nesting at the two Normand colonies shared some of their foraging areas, birds from Boulogne-sur-Mer did not overlap their foraging areas with Normand birds. GPS-tracked birds from all three colonies remained close to the shore (<30 km) and mainly remained within French national waters. The existing MPA network encompassed >60% of all recorded locations, but MPA use was largely colony-specific. Habitat models built to predict habitat suitability confirmed that some MPAs encompassed highly suitable foraging and resting habitats for black-legged kittiwakes in the English Channel. Connectivity between the studied colonies was high, as indicated by inter-colony prospecting movements recorded in two individuals which supposedly failed their reproduction. Overall, this work highlights that marine species such as seabirds could benefit from existing MPAs. Nevertheless, the diversity of MPA types and their different roles complicates their effectiveness to protect marine biodiversity.
Recent international initiatives have promoted a number of different approaches to identify marine Important Bird and biodiversity Areas (IBAs), which are important areas for foraging, migrating or over-wintering seabirds. The ‘Foraging Radius Approach’ is one of these and uses known foraging range and habitat preferences to predict the size and location of foraging areas around breeding colonies. Here we assess the performance of the Foraging Radius Approach using GPS tracking data from six seabird species with a variety of foraging modes. For each species we compared the population home-range areas of our six study species with the home-range areas defined using the Foraging Radius Approach. We also assessed whether basic information on depth preferences from tracking data could improve these home-range area estimates. Foraging Radius Approach home-range areas based on maximum foraging radii encompassed the entire population home-range of five out of six of our study species but overestimated the size of the population home-range area in every case. The mean maximum foraging radius overestimated the population home-range areas by a factor of 4–14 for five of the six species whilst the mean foraging radius overestimated the population home-range area for half of the species and underestimated for the rest. In the absence of other data, the Foraging Radius Approach appears to provide a reasonable basis for preliminary marine IBA identification. We suggest that using the mean value of all previously reported maximum foraging radii, informed by basic depth preferences provides the most appropriate prediction, balancing the needs of seabirds with efficient use of marine space.
Miniaturized data loggers have revolutionized the study of animal movement. However, data obtained from tagging could be compromised by impacts on animal welfare and behavior. We evaluated short-term (activity budgets, foraging trip metrics, overall dynamic body acceleration [ODBA] of flying, wingbeat frequency, adult mass, and nestling mass) and long-term metrics (breeding success and survival) for breeding female Black-legged Kittiwakes (Rissa tridactyla) tagged with both GPS and accelerometer tags (5.2% of body mass), birds tagged with only accelerometers (1.0% of body mass), and untagged birds. Breeding success, survival, adult mass, and nestling masswere not affected by tagging, and there were no differences in trip metrics, ODBA, and flapping frequency for birds tagged with GPS and accelerometer packages vs. only accelerometers. However, accelerometry revealed that, whentagged for 3 days with GPS and accelerometer tags, kittiwakes reduced the amount of time spent flying by 30%. Impacts of short-term tag deployments were detected by measuring metrics over the same short timescale, ratherthan through measurement of long-term metrics. We suggest that tagging birds alters their behavior, but that such effects may not be detected using coarse-scale measures, such as reproductive success, survival, and body mass, dueto behavioral accommodation. We recommend that researchers examine, or at least take into consideration, behavioral changes that may be associated with tagging, even if there are no clear effects on fitness or conditionmeasures.
Summary of the content of a compilation country by country of all IBAs existing in the Americas
Human pressures on the ocean are thought to be increasing globally, yet we know little about their patterns of cumulative change, which pressures are most responsible for change, and which places are experiencing the greatest increases. Managers and policymakers require such information to make strategic decisions and monitor progress towards management objectives. Here we calculate and map recent change over 5 years in cumulative impacts to marine ecosystems globally from fishing, climate change, and ocean- and land-based stressors. Nearly 66% of the ocean and 77% of national jurisdictions show increased human impact, driven mostly by climate change pressures. Five percent of the ocean is heavily impacted with increasing pressures, requiring management attention. Ten percent has very low impact with decreasing pressures. Our results provide large-scale guidance about where to prioritize management efforts and affirm the importance of addressing climate change to maintain and improve the condition of marine ecosystems.
Unprecedented changes to the marine environment and growth of bio-logging science make detailed study of the movement ecology of threatened marine species timely. Here, we study spatial and temporal patterns of marine space use by a critically endangered seabird: the Balearic shearwater Puffinus mauretanicus. Using a suite of bio-logging systems, 67 foraging trips were recorded during incubation periods between 2011 and 2014 from one of the species’ largest colonies (Sa Cella, Mallorca). Most birds followed narrow flight corridors to restricted neritic foraging grounds on the Iberian continental shelf. Productive foraging areas along the Catalan coast (NE Spain) were consistent across multiple years and between sexes, indicating extensive use of predictable resources. While our study emphasises the vulnerability of this species to anthropogenic activity in nearshore waters, consistent commuting corridors and foraging grounds represent tractable habitat for protection and offer hope for developing area-based management approaches. Preferred foraging areas showed strong overlap with recently declared Special Protection Areas, strengthening the evidence base for targeted management at these sites.
Aichi target 11 of the Convention of Biological Diversity promotes the expansion of the global protected area network to cover 17 percent of all terrestrial land and 10 percent of coastal and marine areas by 2020 (www.cbd.int/sp/targets). At the recent World Parks Congress, organized by the International Union for Conservation of Nature (IUCN) in Sydney, Australia, 12 innovative approaches were promoted as part of the “Promise of Sydney” to help transform decisionmaking, policy, capacity, and financing for protected areas in the next decade (http://io.aibs.org/syd). The first of such approaches includes a list of 20 important recommendations to help reach conservation goals. Many of these recommendations are provided for single countries to take action individually. In addition, the final recommendation advocates that a more ambitious target of protection (50 percent global protection) should be promoted to more adequately conserve biodiversity. Both points are problematic: recent research shows that facilitating international collaboration among countries is crucial to identifying and implementing a well-connected system of protected areas that can better represent threatened biodiversity, and setting unrealistic and politically challenging global protection targets is unneeded. This Viewpoint presents three main themes of the recommendations that would benefit from greater emphasis and the promotion of the importance of international collaborations.
We present a new algorithm for behavioural annotation. The EMbC algorithm
(Expectation-Maximization binary Clustering) is a variant of the Gaussian
Mixture Model maximum likelihood estimation algorithm, also known as
Expectation-Maximization Clustering. We focus on the analysis of two movement
variables (velocity and turn) obtained from the successive locations of a
trajectory. We show and discuss the EMbC behavioural annotation outputs in both
simulated and empirical trajectories. We also explore its robustness to data
loss and data inaccuracies, and compare EMbC with expert labelling. Finally, we
suggest a smoothing procedure that better accounts for the temporal
associations among behaviours/labels, and an algorithm to properly visualize
behavioural annotation in movement trajectories.
The EMbC algorithm fills a gap in movement trajectory segmentation procedures
by reaching a good compromise between meaningful and easily interpretable
behavioural segmentation and sound (and robust) statistical performance. As an
unsupervised and non-intensive computing method, the EMbC algorithm is
particularly suited for big data and large scale analyses where comparisons
across species, sampling schemes, tracking technologies, and ecological
contexts are looked for.
Our algorithm is available within the EMbC R-package. The package is linked
to the Move R-package developed by the Movebank team and forwardly deals with
Move objects.
Originally conceived to conserve iconic landscapes and wildlife, protected areas are now expected to achieve an increasingly diverse set of conservation, social and economic objectives. The amount of land and sea designated as formally protected has markedly increased over the past century, but there is still a major shortfall in political commitments to enhance the coverage and effectiveness of protected areas. Financial support for protected areas is dwarfed by the benefits that they provide, but these returns depend on effective management. A step change involving increased recognition, funding, planning and enforcement is urgently needed if protected areas are going to fulfil their potential.
Recent meta-analyses identified conservation hotpots at the scale of the Mediterranean, yet those may be crude by lack of detailed information about the spatial ecology of the species involved. Here, we identify an irreplaceable marine area for >95 % of the world population of the Scopoli’s shearwater (Calonectris diomedea), which is endemic to the Mediterranean and breeds on the island of Zembra off Tunis. To this end, we studied the three-dimensional at-sea movements of 50 breeding adults (over a total of 94 foraging trips) in 2012 and 2013, using GPS and temperature–depth recorders. Feathers were also collected on all birds to investigate their trophic status. Despite Zembra being the largest seabird colony in the Mediterranean (141,000 pairs), the per capita home-range of Scopoli’s shearwaters foraging from this colony was not larger than that of birds from much smaller colonies, indicating highly beneficial feeding grounds in the Gulf of Tunis and off Cap Bon. Considering depleted Mediterranean small pelagic fish stocks, supposed to be Scopoli’s shearwater prey base, we therefore speculate that birds may now also largely feed on zooplankton, something which is supported by our stable isotopic analyses. Crucially, shearwater at-sea feeding and resting areas showed very little overlap with a conservation hotspot recently defined on the western side of the Gulf of Tunis using meta-analyses of species distributions relative to anthropogenic threats. We therefore propose a major extension to this conservation hotspot. Our study stresses the importance of detailed biotelemetry studies of marine megafauna movement ecology for refining large-scale conservation schemes such as marine protected area networks.
Detailed guidance on the application of the IUCN protected area categories to marine protected areas
NOTE: 2nd EDITION (UPDATED) WAS PUBLISHED IN DEC 2019; see Day et al (2019) on ResearchGate @ https://www.researchgate.net/publication/337707449_Guidelines_for_applying_the_IUCN_protected_area_management_categories_to_marine_protected_areas_-_2nd_Edition
We review the conservation status of, and threats to, all 346 species of seabirds, based on BirdLife International’s data and assessments for the 2010 IUCN Red List. We show that overall, seabirds are more threatened than other comparable groups of birds and that their status has deteriorated faster over recent decades. The principal current threats at sea are posed by commercial fisheries (through competition and mortality on fishing gear) and pollution, whereas on land, alien invasive predators, habitat degradation and human disturbance are the main threats. Direct exploitation remains a problem for some species both at sea and ashore. The priority actions needed involve: a) formal and effective site protection, especially for Important Bird Area (IBA) breeding sites and for marine IBA feeding and aggregation sites, as part of national, regional and global networks of Marine Protected Areas; b) removal of invasive, especially predatory, alien species (a list of priority sites is provided), as part of habitat and species recovery initiatives; and c) reduction of bycatch to negligible levels, as part of comprehensive implementation of ecosystem approaches to fisheries. The main knowledge gaps and research priorities relate to the three topics above but new work is needed on impacts of aquaculture, energy generation operations and climate change (especially effects on the distribution of prey species and rise in sea level). We summarise the relevant national and international jurisdictional responsibilities, especially in relation to endemic and globally threatened species.
Thick-billed Uria lomvia near the Nuvuk Islands, NE Hudson Bay, preferred waters 40-120 m in depth. Abundance was correlated with degree of bottom relief. Murre abundance varied with phase in the tidal cycle, but did not consistently reach expected peaks at the midpoints of ebb and flood tides. Murre distributions were highly aggregated in space and time, and were positively correlated with densities of shoaling prey. Thick-billed murre feeding distributions are influenced by coarse-scale (1-100 km) flow gradients. Birds track preferred feeding conditions at the scale of several kilometers. -from Authors
We investigated daily and annual variation in the marine habitat selection of marbled
murrelets Brachyramphus marmoratus (Alcidae) in the nearshore California Current System at scales
of 10 to 100 km of coastline. We addressed 2 general questions: (1) how do murrelets select habitat
while facing dramatic and often rapid variation in oceanographic conditions and prey availability;
and (2) does selection vary between meso- (10 to 100 km) and fine- (<10 km) scales. Marine transects
were performed during 1999 and 2000 to survey murrelets and prey-fish schools, and to collect data
on physical oceanography. We predicted that habitat selection would vary with upwelling intensity
and prey availability: prey-aggregating mechanisms should be more important under low upwelling
scenarios when cool, productive water is more limited, and murrelets should forage closer to nesting
habitat when prey availability is high. This was generally the case, as murrelets selected cooler locations
when upwelling was low and locations closer to nesting habitat when upwelling was high. Interactions
among variables were important; murrelet habitat selection for prey and fronts changed
among different sea surface temperatures (SSTs), distance to nesting habitat, upwelling intensity,
and overall prey availability. Scale-dependent selection for prey patches (fish schools) and fronts
occurred within larger-scale selection for SST or distance from nesting habitat. Additional scaledependent
effects of prey availability were revealed by small-scale surveys in an area of high prey
density. In this case, murrelets selected cool water (higher quality habitat) when prey availability was
low and were associated with prey schools when prey availability was high. Additional large-scale
surveys from 1996 to 2000 revealed that these patterns also manifested themselves on a longer temporal
scale. Murrelets occurred farther from nesting flyways in years when spring upwelling was low
and during the 1998 El Niño Southern Oscillation (ENSO) when local food webs were depressed and
numerous other seabird species failed to reproduce.
We report the first successful use of miniature Global Positioning System loggers to track the ocean-going behaviour of a c . 400 g seabird, the Manx Shearwater Puffinus puffinus . Breeding birds were tracked over three field seasons during the incubation and chick-rearing periods on their foraging excursions from the large colony on Skomer Island, Pembrokeshire, UK. Foraging effort was concentrated in the Irish Sea. Likely foraging areas were identified to the north, and more diffusely to the west of the colony. No foraging excursions were recorded significantly to the south of the colony, conflicting with the conclusions of earlier studies based on ringing recoveries and observations. We discuss several explanations including the hypothesis that foraging may have shifted substantially northwards in recent decades. We found no obvious relationship between birds' positions and water depth, although there was a suggestion that observations at night were in shallower water than those during the day. We also found that, despite the fact that Shearwaters can be observed rafting off-shore from their colonies in the hours prior to making landfall at night, breeding birds are usually located much further from the colony in the last 8 h before arrival, a finding that has significance for the likely effectiveness of marine protection areas if they are only local to the colony. Short sequences of precise second-by-second fixes showed that movement speeds were bimodal, corresponding to sitting on the water (most common at night and around midday) and flying (most common in the morning and evening), with flight behaviour separable into erratic (indicative of searching for food) and directional (indicative of travelling). We also provide a first direct measurement of mean flight speed during directional flight (c . 40 km/h), slower than a Shearwater's predicted maximum range velocity, suggesting that birds are exploiting wave or dynamic soaring during long-distance travel.
Because of their popular appeal, top vertebrate predators have frequently been used as flagship or umbrella species to acquire financial support, raise environmental awareness and plan systems of protected areas. However, some have claimed that the utilization of charismatic predators may divert a disproportionate amount of funding to a few glamorous species without delivering broader biodiversity benefits, an accusation aggravated by the fact that the conservation of top predators is often complex, difficult and expensive. Therefore, tests are needed of whether apex predators may be employed to achieve ecosystem‐level targets.
To test such a hypothesis, we compared the biodiversity values recorded at the breeding sites of six raptor species, differing widely in diet and habitat associations, with those observed at three types of control locations, (i) sites randomly chosen in comparable habitat, (ii) breeding sites of a randomly selected bird species of lower trophic level and (iii) breeding sites of a lower trophic level species with specialized ecological requirements. Biodiversity was measured as the richness and evenness of bird, butterfly and tree species.
Biodiversity levels were consistently higher at sites occupied by top predators than at any of the three types of control sites. Furthermore, sites occupied by top predators also held greater densities of individual birds and butterflies (all species combined) than control sites.
In a reserve‐selection simulation exercise, networks of protected sites constructed on the basis of top predators were more efficient than networks based on lower trophic level species, enabling higher biodiversity coverage to be achieved with a smaller number of reserves.
Synthesis and applications . Our results provide evidence of a link between the strategic utilization of top predatory species and ecosystem‐level conservation. We suggest that, at least in some biological systems, conservation plans based on apex predators could be implemented to deliver broader biodiversity benefits.
Pelagic marine predators face unprecedented challenges and uncertain futures. Overexploitation and climate variability impact the abundance and distribution of top predators in ocean ecosystems. Improved understanding of ecological patterns, evolutionary constraints and ecosystem function is critical for preventing extinctions, loss of biodiversity and disruption of ecosystem services. Recent advances in electronic tagging techniques have provided the capacity to observe the movements and long-distance migrations of animals in relation to ocean processes across a range of ecological scales. Tagging of Pacific Predators, a field programme of the Census of Marine Life, deployed 4,306 tags on 23 species in the North Pacific Ocean, resulting in a tracking data set of unprecedented scale and species diversity that covers 265,386 tracking days from 2000 to 2009. Here we report migration pathways, link ocean features to multispecies hotspots and illustrate niche partitioning within and among congener guilds. Our results indicate that the California Current large marine ecosystem and the North Pacific transition zone attract and retain a diverse assemblage of marine vertebrates. Within the California Current large marine ecosystem, several predator guilds seasonally undertake north-south migrations that may be driven by oceanic processes, species-specific thermal tolerances and shifts in prey distributions. We identify critical habitats across multinational boundaries and show that top predators exploit their environment in predictable ways, providing the foundation for spatial management of large marine ecosystems.
Parsons, M., Mitchell, I., Butler, A., Ratcliffe, N., Frederiksen, M., Foster, S., and Reid, J. B. 2008. Seabirds as indicators of the marine environment. – ICES Journal of Marine Science, 65: 1520–1526.
We report on the development of seabird indicators that support the Scottish Biodiversity Strategy. The application of high-quality monitoring data on breeding abundance and productivity in Scotland was explored in three ways: as indicators of seabird status in its own right, as indicators of the “health” of the marine environment, and as indicators of the food supply of vertebrate predators. Data on breeding productivity of seabirds, which responds more immediately to environmental variation than adult abundance, provided a novel supplement to indicators based solely on abundance trends. Grouping of species according to ecological guilds provided indicators of change in particular aspects of the marine environment. The role of seabird indicators in relation to policy frameworks is discussed, with a look to further developments at the UK and regional scales.
In a patchy environment, predators are expected to increase turning rate and start an area-restricted search (ARS) when prey have been encountered, but few empirical data exist for large predators. By using GPS loggers with devices measuring prey capture, we studied how a marine predator adjusts foraging movements at various scales in relation to prey capture. Wandering albatrosses use two tactics, sit and wait and foraging in flight, the former tactic being three times less efficient than the latter. During flight foraging, birds caught large isolated prey and used ARS at scales varying from 5 to 90 km, with large-scale ARS being used only by young animals. Birds did not show strong responses to prey capture at a large scale, few ARS events occurred after prey capture, and birds did not have high rates of prey capture in ARS. Only at small scales did birds increase sinuosity after prey captures for a limited time period, and this occurred only after they had caught a large prey item within an ARS zone. When this species searches over a large scale, the most effective search rule was to follow a nearly straight path. ARS may be used to restrict search to a particular environment where prey capture is more predictable and profitable.
We propose a continuous-time version of the correlated random walk model for animal telemetry data. The continuous-time formulation allows data that have been nonuniformly collected over time to be modeled without subsampling, interpolation, or aggregation to obtain a set of locations uniformly spaced in time. The model is derived from a continuous-time Ornstein-Uhlenbeck velocity process that is integrated to form a location process. The continuous-time model was placed into a state-space framework to allow parameter estimation and location predictions from observed animal locations. Two previously unpublished marine mammal telemetry data sets were analyzed to illustrate use of the model, by-products available from the analysis, and different modifications which are possible. A harbor seal data set was analyzed with a model that incorporates the proportion of each hour spent on land. Also, a northern fur seal pup data set was analyzed with a random drift component to account for directed travel and ocean currents.
Many industrial activities impose a threat on biodiversity, and it is unclear to what extent environmental regulations can reduce the threat of such activities. Bycatch in industrial fisheries is one of the greatest sources of mortality for seabirds, but a threat for which effective mitigation exists. Here we quantify whether the introduction of a new regulation that required the use of bird-scaring lines reduced seabird mortality in two of the most hazardous fisheries in the South Atlantic. The Namibian hake demersal trawl and longline fisheries, estimated to be killing 20,000–30,000 birds/year, have been required to use bird-scaring lines since 2015. We used data from BirdLife International's Albatross Task Force and the Namibian Fisheries Observer Agency to quantify changes in seabird mortality in these fisheries before and after the introduction of these regulations. Our estimated bycatch rates in the longline fleet were 0.468 birds/1000 hooks (95% confidence interval 0.067–1.450) before regulations and 0.004 birds/1000 hooks (0.001–0.013) following their introduction, a 98.4% reduction. Our estimate suggests that 215 (1–751) seabirds were killed across this fleet in 2018 compared to 22,222 (3187–68,786) in 2009. In the trawl fleet, observers recorded seabird mortality resulting from interactions with trawl cables. The average rate of heavy interactions was 1.09 interactions/h (0.81–1.39) before the regulation came into effect, and 0.49 interactions/h (0.23–0.84) since then. Extrapolations based on the number of observed fatal interactions suggest 1452 (0–3865) birds were killed by this fleet in 2017 compared to 7030 (0–16,374) in 2009. The lower mortality reduction in the trawl fleet is likely due to incomplete implementation of regulations and highlights the importance of adequate enforcement for effective bycatch mitigation. Overall, we demonstrate that regulations that mandate that well-tested safeguards are used during industrial operations can have enormous benefits for the conservation of threatened species.
Almost all classifications of the world ocean are based on expert opinion or ad hoc management areas. A quantitative analysis of environmental variables may provide a more objective basis for mapping and classifying the oceans to support data management, reporting, and conservation efforts. Here, we used long‐term averages of 20 ocean variables to classify the ocean surface waters using PCA and k‐means clustering. We identified seven distinct areas that fit the definition of “ecosystems,” that is, enduring regions demarcated by environmental characteristics. Of all the variables, temperature had the greatest importance and correlated with many other variables. However, some variables had uniquely significant effects on the classification, namely slope, surface current, pH, and wave height. Thus, while the present classification is robust for available data, future analyses with variables not presently available may improve it. How the ecosystems correlate with species richness, endemicity, or abundance will inform on the factors that most influence species' abundance, and thus support global modeling of the effects of climate change, for example, with regard to biological carbon fluxes. This manuscript used k‐means clustering analysis to map global marine ecosystems with 20 environmental variables. The mapped ecosystems were compared with three previous global marine ecological partitions.
We present the first objective quantitative assessment of the threats to all 359 species of seabirds, identify the main challenges facing them, and outline priority actions for their conservation. We applied the standardised Threats Classification Scheme developed for the IUCN Red List to objectively assess threats to each species and analysed the data according to global IUCN threat status, taxonomic group, and primary foraging habitat (coastal or pelagic). The top three threats to seabirds in terms of number of species affected and average impact are: invasive alien species, affecting 165 species across all the most threatened groups; bycatch in fisheries, affecting fewer species (100) but with the greatest average impact; and climate change/severe weather, affecting 96 species. Overfishing, hunting/trapping and disturbance were also identified as major threats to seabirds. Reversing the top three threats alone would benefit two-thirds of all species and c. 380 million individual seabirds (c. 45% of the total global seabird population). Most seabirds (c. 70%), especially globally threatened species, face multiple threats. For albatrosses, petrels and penguins in particular (the three most threatened groups of seabirds), it is essential to tackle both terrestrial and marine threats to reverse declines. As the negative effects of climate change are harder to mitigate, it is vital to compensate by addressing other major threats that often affect the same species, such as invasive alien species, bycatch and overfishing, for which proven solutions exist.
During the breeding season, seabird foraging trips are constrained by nest attendance schedule and are necessarily colony centred. Oceanographic cues play a major role in the choice of foraging areas to minimize the time spent away from the nest. Here, we analysed the foraging tracks of Black‐vented Shearwaters Puffinus opisthomelas during the incubation and chick‐rearing periods of 2016 and 2017 at Isla Natividad (Mexico). We applied expectation‐maximization binary clustering to track data to clusterize different behaviour patterns during foraging flights. We then applied binary generalized linear mixed models to characterize of foraging areas based on of environmental variables. We finally used kernel estimation techniques to describe main foraging areas. In 2016, breeding shearwaters used two core areas for foraging and resting on the water; the core area delineated by males was located northward from the colony in the Vizcaino Bay and the core area for females was located southward from the colony at the entrance of San Ignacio Lagoon. In 2017, males and females used the same areas with no evident segregation. Our study provided the first information on Black‐vented Shearwater foraging areas during the breeding season and indicated that sexual segregation within coastal waters off the central Baja California Peninsula might be a foraging strategy during years of warmer ocean, likely less productive regimes. Factors including ocean‐climate‐mediated sexual segregation at sea, leading to interannual variation in foraging areas, should be considered when evaluating management actions intended to protect critical foraging habitats for Black‐vented Shearwaters.
Important Bird and Biodiversity Areas (IBAs) are sites identified as being globally important for the conservation of bird populations on the basis of an internationally agreed set of criteria. We present the first review of the development and spread of the IBA concept since it was launched by BirdLife International (then ICBP) in 1979 and examine some of the characteristics of the resulting inventory. Over 13,000 global and regional IBAs have so far been identified and documented in terrestrial, freshwater and marine ecosystems in almost all of the world’s countries and territories, making this the largest global network of sites of significance for biodiversity. IBAs have been identified using standardised, data-driven criteria that have been developed and applied at global and regional levels. These criteria capture multiple dimensions of a site’s significance for avian biodiversity and relate to populations of globally threatened species (68.6% of the 10,746 IBAs that meet global criteria), restricted-range species (25.4%), biome-restricted species (27.5%) and congregatory species (50.3%); many global IBAs (52.7%) trigger two or more of these criteria. IBAs range in size from < 1 km ² to over 300,000 km ² and have an approximately log-normal size distribution (median = 125.0 km ² , mean = 1,202.6 km ² ). They cover approximately 6.7% of the terrestrial, 1.6% of the marine and 3.1% of the total surface area of the Earth. The launch in 2016 of the KBA Global Standard, which aims to identify, document and conserve sites that contribute to the global persistence of wider biodiversity, and whose criteria for site identification build on those developed for IBAs, is a logical evolution of the IBA concept. The role of IBAs in conservation planning, policy and practice is reviewed elsewhere. Future technical priorities for the IBA initiative include completion of the global inventory, particularly in the marine environment, keeping the dataset up to date, and improving the systematic monitoring of these sites.
BirdLife International´s Important Bird and Biodiversity Areas (IBA) Programme has identified, documented and mapped over 13,000 sites of international importance for birds. IBAs have been influential with governments, multilateral agreements, businesses and others in: (1) informing governments’ efforts to expand protected area networks (in particular to meet their commitments through the Convention on Biological Diversity); (2) supporting the identification of Ecologically or Biologically Significant Areas (EBSAs) in the marine realm, (3) identifying Wetlands of International Importance under the Ramsar Convention; (4) identifying sites of importance for species under the Convention on Migratory Species and its sister agreements; (5) identifying Special Protected Areas under the EU Birds Directive; (6) applying the environmental safeguards of international finance institutions such as the International Finance Corporation; (7) supporting the private sector to manage environmental risk in its operations; and (8) helping donor organisations like the Critical Ecosystems Partnership Fund (CEPF) to prioritise investment in site-based conservation. The identification of IBAs (and IBAs in Danger: the most threatened of these) has also triggered conservation and management actions at site level, most notably by civil society organisations and local conservation groups. IBA data have therefore been widely used by stakeholders at different levels to help conserve a network of sites essential to maintaining the populations and habitats of birds as well as other biodiversity. The experience of IBA identification and conservation is shaping the design and implementation of the recently launched Key Biodiversity Areas (KBA) Partnership and programme, as IBAs form a core part of the KBA network.
Knowing the spatial scales at which effective management can be implemented is fundamental for conservation
planning. This is especially important for mobile species, which can be exposed to threats across large areas, but
the space use requirements of different species can vary to an extent that might render some management
approaches inefficient. Here the space use patterns of seabirds were examined to provide guidance on whether
conservation management approaches should be tailored for taxonomic groups with different movement characteristics.
Seabird tracking data were synthesised from 5419 adult breeding individuals of 52 species in ten
families that were collected in the Atlantic Ocean basin between 1998 and 2017. Two key aspects of spatial
distribution were quantified, namely how far seabirds ranged from their colony, and to what extent individuals
from the same colony used the same areas at sea. There was evidence for substantial differences in patterns of
space-use among the ten studied seabird families, indicating that several alternative conservation management
approaches are needed. Several species exhibited large foraging ranges and little aggregation at sea, indicating
that area-based conservation solutions would have to be extremely large to adequately protect such species. The
results highlight that short-ranging and aggregating species such as cormorants, auks, some penguins, and gulls
would benefit from conservation approaches at relatively small spatial scales during their breeding season.
However, improved regulation of fisheries, bycatch, pollution and other threats over large spatial scales will be
needed for wide-ranging and dispersed species such as albatrosses, petrels, storm petrels and frigatebirds.
We begin our series of empirical cases with a small Mexican fishing cooperative, located close to the border with the USA. This example provides a link between the cooperative system and environmental issues. Natividad is a tiny and arid island, six by two kilometres, off Baja California’s coast in Mexico. Barely 400 people (80 families) live there. Life on the island depends entirely upon the Natividad Divers’ and Fishermen’s Cooperative, which exploits the maritime areas according to a concession contract with the government. The divers spend four to five hours every day under the water, linked to an oxygen tube and assisted by colleagues on a small boat above them. They mainly gather abalones, a very rare and expensive shellfish, and they earn a lot of money: a diver can earn up to US$10,000 a month.
Aim
Enhanced management of areas important for marine biodiversity are now obligations under a range of international treaties. Tracking data provide unparalleled information on the distribution of marine taxa, but there are no agreed guidelines that ensure these data are used consistently to identify biodiversity hotspots and inform marine management decisions. Here, we develop methods to standardize the analysis of tracking data to identify sites of conservation importance at global and regional scales.
Location
We applied these methods to the largest available compilation of seabird tracking data, covering 60 species, collected from 55 deployment locations ranging from the poles to the tropics.
Methods
Key developments include a test for pseudo‐replication to assess the independence of two groups of tracking data, an objective approach to define species‐specific smoothing parameters ( h values) for kernel density estimation based on area‐restricted search behaviour, and an analysis to determine whether sites identified from tracked individuals are also representative for the wider population.
Results
This analysis delineated priority sites for marine conservation for 52 of the 60 species assessed. We compiled 252 data groupings and defined 1052 polygons, between them meeting Important Bird and Biodiversity Area criteria over 1500 times. Other results showed 13% of data groups were inadequate for site definition and 10% showed some level of pseudo‐replication. Between 25 and 50 trips were needed within a data group for data to be considered at least partially representative of the respective population.
Main conclusions
Our approach provides a consistent framework for using animal tracking data to delineate areas of global conservation importance, allowing greater integration into marine spatial planning and policy. The approaches we describe are exemplified for pelagic seabirds, but are applicable to a range of taxonomic groups. Covering 4.3% of the oceans, the sites identified would benefit from enhanced protection to better safeguard the threatened species populations they contain.
This paper reports recent at-sea sightings of the little-known Heinroth's shearwater (Puffinus heinrothi) within the Solomon Islands. Feeding habits are described and compared to those of black noddy (Anous minutus). Observations suggest that Heinroth's shearwater occurs in dark, intermediate and pale forms, and may be better considered as a polymorphic species.
The Aichi Biodiversity Targets were designed to promote and implement the Convention on Biological Diversity (CBD) by providing a framework for action to save biodiversity and enhance its benefits for people. Specifically, Target 11 aims to protect 10% of all seas by 2020. The percentage of the world's oceans that are protected has increased steadily in recent years, mainly due to very large marine protected areas (MPAs).
The issue of making major gains in achieving protection targets through ‘going big’ has brought added scrutiny to the subject of MPAs. There is economy in scale, but several people have called into question whether going large will protect representative habitat and result in true protection, or whether it is merely a politically expedient way for some nations to attain targets by creating paper parks, while avoiding tough conservation decisions.
The recent creation of large MPAs has greatly enhanced the chance of achieving global protection targets. Large areas typically contain several ecosystems and habitats that interact ecologically, and allow for more holistic conservation. The interactions between ecosystems in large MPAs occur without many of the problems associated with networks of smaller MPAs, where the connectivity between sites is often affected by human activities.
The disadvantages of large MPAs include difficulties of surveillance, enforcement and monitoring of vast offshore areas, as well as high total costs. While the cost per unit area may be lower for large MPAs, conducting surveillance and monitoring in such vast areas requires much more expensive technologies.
Large MPAs complement and add to existing management and conservation measures. Decision makers should consider designating them as one of a suite of possible protection measures. Besides greatly enhancing the chance of reaching agreed biodiversity targets, large MPAs improve the quality of conservation.
Copyright © 2014 John Wiley & Sons, Ltd.
Quantitative assessment of the spatial patterns of all human uses of the oceans and their cumulative effects is needed for implementing ecosystem-based management, marine protected areas, and ocean zoning. Here, we apply methods developed to map cumulative impacts globally to the California Current using more comprehensive and higher-quality data for 25 human activities and 19 marine ecosystems. This analysis indicates where protection and threat mitigation are most needed in the California Current and reveals that coastal ecosystems near high human population density and the continental shelves off Oregon and Washington are the most heavily impacted, climate change is the top threat, and impacts from multiple threats are ubiquitous. Remarkably, these results were highly spatially correlated with the global results for this region (R2= 0.92), suggesting that the global model provides guidance to areas without local data or resources to conduct similar regional-scale analyses.
The California Current System (CCS) is forced by the distribution of atmospheric pressure and associated winds in relation to the west coast of North America. In this paper, we begin with a simplified case of winds and a linear coast, then consider variability characteristic of the CCS, and conclude by considering future change. The CCS extends from the North Pacific Current (∼50°N) to off Baja California, Mexico (∼15–25°N) with a major discontinuity at Point Conception (34.5°N). Variation in atmospheric pressure affects winds and thus upwelling. Coastal, wind-driven upwelling results in nutrification and biological production and a southward coastal jet. Offshore, curl-driven upwelling results in a spatially large, productive habitat. The California Current flows equatorward and derives from the North Pacific Current and the coastal jet. Dominant modes of spatial and temporal variability in physical processes and biological responses are discussed. High surface production results in deep and bottom waters depleted in oxygen and enriched in carbon dioxide. Fishing has depleted demersal stocks more than pelagic stocks, and marine mammals, including whales, are recovering. Krill, squid, and micronekton are poorly known and merit study. Future climate change will differ from past change and thus prediction of the CCS requires an understanding of its dynamics. Of particular concern are changes in winds, stratification, and ocean chemistry.
We used satellite telemetry, remotely sensed data (bathymetry, chlorophyll a (chl a), sea-surface temperature (SST), wind speed) and first-passage time (FPT) analysis to determine the distribution, movement patterns, and habitat associations of short-tailed albatrosses (Phoebastria albatrus) during the non-breeding season, 2002 and 2003. Satellite transmitters were deployed on birds immediately prior to their departure from a breeding colony at Torishima, Japan (n=11), or at-sea in the Aleutian Islands (n=3). Tracking durations ranged from 51 to 138 days for a total of 6709 locations after filtering (131 – 808 per bird). FPT (time required to transit a circle of given radius) revealed the location and spatial scale of area-restricted search (ARS) patterns along flight paths. On average, ARS occurred within 70 km radii. Consequently, the fit of the habitat use models increased at spatial scales beyond a 40 km FPT radius (R2=0.31) and stabilized for scales of 70 km and larger (R2=0.40– 0.51). At all scales, wind speed, depth or depth gradient, and chl a or chl a gradient had a significant effect on FPT (i.e., residence time). FPT increased within regions of higher gradients of depth and chl a. In contrast, FPT decreased within regions of greater depth and wind speed, with a significant interaction of wind speed and depth at some scales. Sea-surface temperature or its interactions were only significant at large spatial scales (⩾160 km FPT radius). Albatrosses engaged in ARS activities primarily over the shelf break and slope, including Kuroshio and Oyashio regions off the western subarctic gyre. Occasionally, birds transited the northern boundary of the Kuroshio Extension while in-route to the Aleutian Islands and Bering Sea, but overall spent little time in the western gyre. In the Aleutian Islands, ARS occurred within straits, particularly along the central and western part of the archipelago. In the Bering Sea, ARS occurred along the northern continental shelf break, the Kamchatka Current region, and east of the Commander Islands. Non-breeding short-tailed albatross concentrate foraging in oceanic areas characterized by gradients in topography and water column productivity. This study provides an understanding of the foraging ecology for a highly migratory, imperiled seabird, and confirms the importance of shelf break and slope regions as hot spots for a variety of top marine predators in the North Pacific.