Paul Tixier

Paul Tixier
Institute of Research for Development | IRD · UMR 248 MARBEC

PhD
Researcher at MARBEC Université de Montpellier-CNRS-IFREMER-IRD

About

69
Publications
20,552
Reads
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922
Citations
Additional affiliations
December 2016 - January 2021
Deakin University
Position
  • Research fellow
August 2012 - November 2015
French National Centre for Scientific Research
Position
  • PostDoc Position
October 2009 - July 2012
French National Centre for Scientific Research
Position
  • PhD Student

Publications

Publications (69)
Article
Full-text available
Prey availability is a critical factor influencing demographic trajectories of long-lived, top predators, which may therefore be strongly affected by artificial food provisioning. In the Crozet archipelago, killer whales feed on a wide range of species including birds, marine mammals and fish. Following the development of the Patagonian toothfish f...
Article
Full-text available
Individual heterogeneity in foraging behavior has been widely documented within predator populations. In highly social apex predators such as killer whales (Orcinus orca), specialization may occur at the matriline level. A small population of killer whales has been documented to occur around the Crozet Islands. These whales feed on a wide range of...
Article
Fisheries may generate new feeding opportunities for marine predators, which switch foraging behaviour to depredation when they feed on fish directly from fishing gear. However, the role of diet in the propensity of individuals to depredate and whether the depredated resource is artificial or part of the natural diet of individuals is often unclear...
Article
The sustainable mitigation of human–wildlife conflicts has become a major societal and environmental challenge globally. Among these conflicts, large marine predators feeding on fisheries catches, a behaviour termed “depredation,” has emerged concomitantly with the expansion of the world’s fisheries. Depredation poses threats to both the socio‐econ...
Article
Fisheries can generate feeding opportunities for large marine predators in the form of discards or accessible catch. How the use of this anthropogenic food may spread as a new behaviour, across individuals within populations over time, is poorly understood. This study used a 16-year (2003–2018) monitoring of two killer whale Orcinus orca subantarct...
Article
Large marine predators feeding on fish caught on fishing gear, a behaviour termed as depredation, can incur socio-economic costs for fisheries and have serious implications on the depredating species, fish stocks and associated ecosystems. The quantity of depredated fish as well as the quantity of depredated fish relative to the retained catch dict...
Article
Full-text available
Adult male sperm whales (Physeter macrocephalus) are long distance runners of the marine realm, feeding in high latitudes and mating in tropical and subtropical waters where stable social groups of females and immatures live. Several areas of uncertainty still limit our understanding of their social and breeding behavior, in particular concerning t...
Article
Full-text available
Commerson’s dolphins ( Cephalorhynchus commersonii ) are separated into the subspecies C. c. commersonii , found along southern South America (SA) and the Falkland Islands/Islas Malvinas (FI/IM), and C. c. kerguelenensis , restricted to the subantarctic Kerguelen Islands (KI). Following the dispersal model proposed for the genus, the latter is thou...
Article
Full-text available
Removal of fish from gear by marine predators, known as depredation, is a fishery dependent mortality that needs to be included in stock assessments for affected stocks to avoid misestimation of the assessed resource. Toothed whales engage regularly in depredation from longlines, and while in some regions they leave clear marks of depredation activ...
Article
Runs of homozygosity (ROH) occur when offspring inherit haplotypes that are identical by descent from each parent. Length distributions of ROH are informative about population history; specifically, the probability of inbreeding mediated by mating system and/or population demography. Here, we investigate whether variation in killer whale (Orcinus o...
Preprint
Runs of homozygosity (ROH) occur when offspring inherit haplotypes that are identical by descent from each parent. Length distributions of ROH are informative about population history; specifically the probability of inbreeding mediated by mating system and/or population demography. Here, we investigate whether variation in killer whale (Orcinus or...
Article
Full-text available
Fisheries modify prey availability for marine predators by extracting resources but also by providing them with new feeding opportunities. Among these, depredation, which occurs when predators feed on fish caught on fishing gear, is a behavior developed by many species as a way to acquire food through limited foraging effort. However, the extent to...
Article
Full-text available
Fishers aim to optimise cost-benefit ratios of their behaviour when exploiting resources. Avoidance of interactions with marine predators (i.e. their feeding on catches in fishing gear, known as depredation), has recently become an important component of their decisions. How fishers minimise these interactions whilst maximising fishing success is p...
Preprint
Full-text available
Adult male sperm whales (Physeter macrocephalus) are long distance runners of the marine realm, feeding in high latitudes and mating in tropical and subtropical waters where stable social groups of females and immatures live. Several areas of uncertainty still limit our understanding of their social and breeding behaviour, in particular concerning...
Technical Report
Full-text available
TThree forms of killer whales (Orcinus orca) occur around the subantarctic islands of the southern Indian Ocean (42-53°S; 34-74°E). The form encountered in both inshore and offshore waters, described as generalist in its feeding preferences (seals, whales, penguins and fish as prey) and known to depredate toothfish from longliners has been opportun...
Article
Removal of target catch from longlines by marine mammals, known as depredation, is a global issue creating animal welfare, socioeconomic and management concerns. The killer whale (Orcinus orca) is a key species of concern for longline depredation due to their global presence and ability to remove large quantities of caught fish. Currently, data on...
Article
Ecosystem-based approaches are increasingly used in fisheries management to account for the direct trophic impacts of fish population harvesting. However, fisheries can also indirectly alter ecosystem structure and functioning, for instance via the provision of new feeding opportunities to marine predators. For instance, marine depredation, where p...
Article
Full-text available
The massive number of seabirds (penguins and procellariiformes) and marine mammals (cetaceans and pinnipeds) – referred to here as top predators – is one of the most iconic components of the Antarctic and Southern Ocean. They play an important role as highly mobile consumers, structuring and connecting pelagic marine food webs and are widely studie...
Article
Full-text available
Marine predators feeding on fisheries catches directly on the fishing gear, a behaviour termed “depredation”, has emerged as a major human-wildlife conflict globally, often resulting in substantial socio-economic and ecological impacts. This study investigated the extent of this conflict in commercial Patagonian toothfish (Dissostichus eleginoides)...
Conference Paper
Full-text available
The emergence of longline fishing for Patagonian toothfish (Dissostichus eleginoides) on the Kerguelen Plateau over the past two decades is concomitant with the development of depredation-type interactions by sperm whales (Physeter macrocephalus). Through a unique collaboration between the French and the Australian fisheries operating respectively...
Conference Paper
Full-text available
Fishing activities targeting Patagonian toothfish (Dissostichus eleginoides) are conducted year round on the edge of the Kerguelen plateau. Since the early 2000s, scientific observers on board have been asked to collect data on both seabird and marine mammal abundances using standard protocols. Data collection is constrained in space (fishing activ...
Article
In highly social top predators, group living is an ecological strategy that enhances individual fitness, primarily through increased foraging success. Additive mortality events across multiple social groups in populations may affect the social structure, and therefore the fitness, of surviving individuals. This hypothesis was examined in a killer w...
Article
Full-text available
Toothed whales (odontocetes) feeding on fish caught on hooks in longline fisheries is a growing issue worldwide. The substantial impacts that this behaviour, called depredation, can have on the fishing economy, fish stocks and odontocetes populations, raise a critical need for mitigation solutions to be developed. However, information on when, wher...
Article
Reconstruction of the demographic and evolutionary history of populations assuming a consensus tree‐like relationship can mask more complex scenarios, which are prevalent in nature. An emerging genomic toolset, which has been most comprehensively harnessed in the reconstruction of human evolutionary history, enables molecular ecologists to elucidat...
Article
Full-text available
The emergence of longline fishing around the world has been concomitant with an increase in depredation-interactions by odontocete whales (removal of fish caught on hooks), resulting in substantial socio-economic and ecological impacts. The extent, trends and underlying mechanisms driving these interactions remain poorly known. Using long-term (200...
Preprint
Full-text available
Reconstruction of the demographic and evolutionary history of populations assuming a consensus tree-like relationship can mask more complex scenarios, which are prevalent in nature. An emerging genomic toolset, which has been most comprehensively harnessed in the reconstruction of human evolutionary history, enables molecular ecologists to elucidat...
Article
Marine mammal depredation on fisheries (animals removing fish caught on fishing gear) is a worldwide issue involving socioeconomic and ecological consequences. Longline fisheries are the most impacted by odontocete (toothed whales) depredation. While technological means have provided limited efficacy in reducing depreda-tion, this study examined th...
Article
Full-text available
Depredation of demersal longlines by killer and sperm whales is a widespread behaviour that impacts fisheries and whale populations. To better understand how depredating whales behave in response to fishing activity, we deployed satellite-linked location and dive-profile tags on a sperm and killer whale that were depredating Patagonian toothfish fr...
Article
Full-text available
Over the past five decades, marine mammal interactions with fisheries have become a major human-wildlife conflict globally. The emergence of longline fishing is concomitant with the development of depredation-type interactions i.e., marine mammals feeding on fish caught on hooks. The killer whale ( Orcinus orca ) is one of the species most involved...
Data
Code (R Markdown) for the analysis used to model (Generalised Linear Models) the occurrence of killer whale interactions with longline fishing vessels in Amsterdam/St. Paul and SE Australia during fishing days
Data
Summary output and parameter estimates of the best GLM-type model fitted with a binomial distribution on the presence/absence records of killer whale interaction with blue eye trevalla longline sets during fishing days Continuous predictors were the year, the latitude, the longitude, the depth at which vessels operated during fishing days, as well...
Data
Daily fishing operations and occurrence of killer whale interaction data used for Generalised Linear Models in Amsterdam/St. Paul and SE Australia
Data
Predictors considered in the Generalised Linear Models fitted to the occurrence of killer whale interactions during fishing days, whether they were included as continuous terms or factors, their unit, range of values or levels
Data
Analysis of the occurrence of killer whale interactions Code for Generalised Linear Models fitted to the presence/absence of killer whales during fishing days
Poster
Full-text available
Highlights - Sperm whales removed toothfish during 61% (Crozet) and 41% (Kerguelen) of hauled longline sets. Periods of low sperm whale presence were during winter months. Sperm whales did not follow fishing vessels over distances greater than 60 km. Depredation was more difficult at hauling speeds beyond of 60 hooks per minute. Depredation has bee...
Data
Method in details on the way estimations of CPUE loss per sperm whale individual were calculated from mathematical equation of Model 3 and model estimates provided in Table 3.
Article
Age and sex dependent spatial segregation has resulted in limited knowledge of the ecology and demography of sperm whale adult males feeding seasonally in high latitudes. This study focused on adult males interacting with the Patagonian toothfish (Dissostichus eleginoides) fishery operating off the Kerguelen and Crozet Archipelagos. Demographic par...
Article
Full-text available
Depredation in longline fisheries by odontocete whales is a worldwide growing issue, having substantial socio-economic consequences for fishers as well as conservation implications for both fish resources and the depredating odontocete populations. An example of this is the demersal longline fishery operating around the Crozet Archipelago and Kergu...
Article
Full-text available
Sympatric forms of ecologically distinctive killer whales (Orcinus orca) have been documented worldwide. This study focused on a new case of such sympatric occurrence of the “Crozet” type and the recently described “type D” killer whales off the Crozet Islands. The two ecotypes are morphologically and genetically distinct, but they both depredate t...
Article
Full-text available
A large, but poorly studied, bottlenose dolphin community, Tursiops truncatus, inhabits coastal waters of Normandy (Normano-Breton Gulf, English Channel, France). In this study, the social structure and abundance of this community were assessed using photo-identification techniques. Like other bottlenose dolphin communities worldwide, this resident...
Article
A large, but poorly studied, bottlenose dolphin community, Tursiops truncatus, inhabits coastal waters of Normandy (Normano-Breton Gulf, English Channel, France). In this study, the social structure and abundance of this community were assessed using photo-identification techniques. Like other bottlenose dolphin communities worldwide, this resident...
Article
Full-text available
Odontocete depredation on longlines involves socioeconomic and conservation issues with significant losses for fisheries and potential impacts on wild populations of depredating species. As technical solutions to this conflict are limited and difficult to implement, this study aimed to identify fishing practices that could reduce odontocete depreda...
Article
Full-text available
Acoustic harassment devices (AHDs) have been increasingly implemented in various fisheries that suffer significant losses caused by odontocete depredation. However, the efficacy of AHDs to deter odontocetes from fishing gear remains poorly investigated. To determine the effectiveness of AHDs in deterring depredation, we experimentally tested a high...
Article
Full-text available
Depredation is a human-wildlife interaction over access to resources, which often includes a combination of socio-economic, ecological and conservation issues. However, estimating the amount of resource depredated can be especially challenging when depredation occurs on fish in the marine environment. This is the case for killer whales (Orcinus orc...
Article
Full-text available
This paper provides a synthesis of results obtained as part of a long-term collaborative study involving biologists, fishers, and resource managers—centring on the occurrence of killer whales in the Crozet Archipelago before and after the implementation of a demersal longline fishery for Patagonian toothfish. Depredation behaviour was reported as s...
Data
Photo-identification of killer whale individuals encountered around the Crozet islands, including two morphotypes: the so called "Crozet killer whales" and the "Type-D" killer whales.
Article
Full-text available
Over the last 50 years, fisheries have undergone a major decline worldwide. With an increased competition for resource, depredation (i.e. removal of catches on fishing gear) has recently become a major case of conflict between humans and marine predators. In this study I focused on the depredation on Patagonian toothfish fisheries by killer and spe...
Article
Full-text available
Depredation is defined as the damage or removal of fish from fishing gear by predators, and is a crucial issue leading to negative impacts on both animals involved in depredation and fisheries. Depredation in longline pelagic fisheries targeting swordfish (Xiphias gladius) and tuna (Thunnus spp.) involves short-finned pilot whales (Globicephala mac...
Technical Report
Full-text available
The CCAMLR MPA Workshop on Marine Protected Areas, held in Brest (France) in August 2011, recommended that the Scientific Committee considers supporting three technical workshops including one specific to Planning Domain 5. Planning Domain 5 includes Marion and Prince Edward Islands, the Del Cano Rise and the Crozet Archipelago in the north. It als...