United States

**Abstract:**

Seabirds and fisheries often compete for the similar pelagic resources, i.e. forage fish. Fisheries management, where present, normally focuses on maximizing long-term harvest (BMSY), which may or may not be compatible with conservation of fish-eating seabirds. We investigate the compatibility between different fisheries management targets and seabird productivity using a bio-energetic model that mechanistically links fish abundance with seabird foraging and energy expenditure. We parameterize the model for a large colony of common murres Uria aalge and razorbills Alca torda in the Baltic Sea (57° N, 17° E) and show that current fisheries management targets for their main prey, sprat Sprattus sprattus and herring Clupea harengus allows for further seabird population growth. This finding is consistent with observed increases in abundance of both species. We validate the model with regards to seabird-driven depletion of prey around the colony, using an unmanned surface vessel (USV) equipped with a broadband echo-sounder. The USV, a sailing drone remotely operated via satellite communication, was used for 40 days around the colony in 2019 with plans for re-deployment in April - July 2020. It provides continuous measurements of acoustic backscatter which is translated into area, time and depth specific biomass estimates for the forage fish. We discuss how USV technology in combination with seabird biologging and bio-energetic modelling can provide estimations of prey needed to sustain important seabird colonies, relevant to forage fish management.

**Authors:**

Jonas Hentati Sundberg¹, Agnes Olin², Natalie Isaksson³, Tom Evans⁴, Per-Arvid Berglund⁵, Aron Hejdström⁶, Olof Olsson⁷

¹Swedish University of Agricultural Sciences, ²University of Strathclyde, ³University of the highlands and islands, ⁴Marine Scotland, ⁵Baltic Seabird Project &amp; Swedish Museum of Natural History, ⁶Baltic Seabird Project, ⁷Stockholm University

3rd World Seabird Conference

Sustainable fisheries for seabirds: Defining prey density thresholds through a combination of bio-energetic modeling, bio-logging and an unmanned surface vessel

Welcome Seabirders!  

Welcome to Virtual World Seabird Conference 3 - vWSC3! Whether you are in your office or lab, at home, in a coffee shop or bar poaching some wifi, or at a remote field site or research vessel – we are very excited to welcome you to the third ever World Seabird Conference. 

We would like to thank ALL of you for being so patient as WSC3 was scheduled, postponed, rescheduled, revised to virtual, and scheduled again. Throughout all those iterations there was one message that remained perfectly clear – seabirders were eager to meet and share their science. If we could not meet in person then virtual it would have to be, but a 3rd WSC was something everyone wanted. That support and commitment helped the WSU Board of Directors and Member Societies sort through all of the challenges they faced to plan and hold this conference. 

The list of those that need to be thanked is long and, while we plan on recognizing many during the live closing plenary, it is important to do so here in writing as well. 

The Australasian Seabird Group was our Local Host for our plan to meet in Hobart, Tasmania. They invested substantial time and effort to find venues and plan events that we unfortunately were not able to visit. Nonetheless we appreciate their work on behalf of WSC3 and encourage all of you to thank them when you see their members in Gathertown or elsewhere during our virtual meeting. Their willingness to host created the initial excitement for WSC3 and without that our vWSC would not have been possible.

We also wish to thank the Science Program Committee, the Virtual Committee, and the Early Career Scientist Committee for their hard work planning the logistics, events, and schedule for vWSC3. These committees also had to deal with changing parameters and short timelines that made what is always a challenging task even more challenging. The Travel Awards Committee also invested time and effort in developing procedures for awarding travel funds that ultimately would not be implemented. 

Our ability to shift from an in-person to a virtual meeting, and to do so in a way that would be financially feasible, was due to the effective efforts of The International Fundraising Committee and to our financial sponsors. The IFC raised funds to support WSC3 and then, through the good relationships they built with sponsors, ensured we could re-envision how those funds could be used to support a virtual conference that would be affordable and high-quality.

We all owe the WSU Board of Directors and the Representatives of the Member Societies a great deal of thanks. They are the ones who manage the WSU and, for the past 18 months, have had to have a series of challenging meetings and conversations, have had to make a series of difficult choices, have had to do all of that while considering the short- and long-term health of WSU and the World Seabird Conferences, and did this while also managing their own challenges at their day jobs. We are grateful for their diligence, patience, foresight, and throughout all of the meetings, their collegiality. Also – a 6-year term is quite a commitment!

There would not be a WSC3 without a successful WSC1 and WSC2. Thanks go to the Pacific Seabird Group for their support of WSC1 in Victoria, Canada, and to the African Seabird Group for their support of WSC2 in Cape Town, South Africa. In each of these endeavors and for our current conference we were fortunate to work with a dependable and trustworthy partner in Podium Conferences. Michelle Smith and Marischal de Armond have become valued members of our team and have not only helped us plan conferences but have assisted and advised the WSU Chairs and Board on issues above and beyond conference planning. 

As we embark on our vWSC3 week we extend to all of you our thanks for showing up, for being patient, and most importantly for the work you do with seabirds. We are all part of a unique, global community that shares an interest, a fascination, and a passion for birds that make a living in our world’s oceans. We have advanced the science, conservation, and management of seabirds as well the ecosystems they inhabit. We are consistently impressed and motivated by the work you do. 

The WSU formed in 2010 because we saw the need for a global organization to address challenges at a global level. Over the past 11 years WSU has grown, adapted, and evolved to become the community that this week is making vWSC3 a reality. Enjoy the week, appreciate and support the friends and colleagues you have made in the community, and if you see us in a virtual hallway please stop and say hello! 

Thank you for the opportunity to serve all of you and the WSU over the past few years,

Nicholas Carlile, Interim Chair, WSU<br>
Patrick Jodice, 2nd Chair of the WSU<br><br>

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Join us for four days of science, networking and virtual engagement with delegates from around the world!

**Abstract:**

Seabirds and fisheries often compete for the similar pelagic resources, i.e. forage fish. Fisheries management, where present, normally focuses on maximizing long-term harvest (BMSY), which may or may not be compatible with conservation of fish-eating seabirds. We investigate the compatibility between different fisheries management targets and seabird productivity using a bio-energetic model that mechanistically links fish abundance with seabird foraging and energy expenditure. We parameterize the model for a large colony of common murres Uria aalge and razorbills Alca torda in the Baltic Sea (57° N, 17° E) and show that current fisheries management targets for their main prey, sprat Sprattus sprattus and herring Clupea harengus allows for further seabird population growth. This finding is consistent with observed increases in abundance of both species. We validate the model with regards to seabird-driven depletion of prey around the colony, using an unmanned surface vessel (USV) equipped with a broadband echo-sounder. The USV, a sailing drone remotely operated via satellite communication, was used for 40 days around the colony in 2019 with plans for re-deployment in April - July 2020. It provides continuous measurements of acoustic backscatter which is translated into area, time and depth specific biomass estimates for the forage fish. We discuss how USV technology in combination with seabird biologging and bio-energetic modelling can provide estimations of prey needed to sustain important seabird colonies, relevant to forage fish management.

**Authors:**

Jonas Hentati Sundberg¹, Agnes Olin², Natalie Isaksson³, Tom Evans⁴, Per-Arvid Berglund⁵, Aron Hejdström⁶, Olof Olsson⁷

¹Swedish University of Agricultural Sciences, ²University of Strathclyde, ³University of the highlands and islands, ⁴Marine Scotland, ⁵Baltic Seabird Project & Swedish Museum of Natural History, ⁶Baltic Seabird Project, ⁷Stockholm University

poster

**Abstract:**

Haematologic analyses can reveal the physiological condition of birds, who are known to efficiently disguise symptoms of stress and disease. However, interpretation of such analyses requires species-specific baseline data, which are lacking for most free-living seabird species. We provide baseline reference data for several haematological parameters in Northern gannets (Morus bassanus) and combine this with telemetry and dietary data to understand the links between haemotologic condition and foraging behaviour. Blood samples were collected from breeding Northern gannets in July 2017 (n = 15) and 2018 (n = 28), which were also equipped with GPS tags. Smears were prepared for performing blood cell counts, including immature erythrocyte and microcyte percentages, total and differential leucocyte counts, heterophil:lymphocyte (H:L) ratio, and total thrombocyte count; the remaining blood was used for stable isotope analysis, and foraging behaviours were inferred from the recovered tag data. Blood cell counts revealed that the sampled birds were highly stressed and some showed an immune response, evident from the abnormal leucocyte counts and H:L ratio. There were no sex-related differences in haematological parameters or diet, in contrast to foraging parameters where females undertook longer trips than males and spent proportionately more time in search behaviours. The percentage time spent actively foraging was negatively correlated with the percentage of eosinophils. While there was no direct link between haematologic condition and diet, one bird feeding at a relatively low trophic level undertook exceptionally short foraging trips and showed abnormal blood cell counts. This suggests a link between haematologic condition and foraging ecology that can be employed in assessing seabird health.

**Authors:**

Zaraa Malvat¹, Sharon Lynch¹, Ashley Bennison¹, Mark Jessopp¹

¹University College Cork

Evidence of links between haematologic condition and foraging behaviour in Northern gannets (Morus bassanus)

**Abstract:**

Artificial night lighting and its consequent light pollution cause high mortality events on burrow nesting seabirds, particularly petrels and shearwaters. Mainly fledglings are attracted and disorientated by artificial lights during their naïve nocturnal flights from their natal nests towards the sea. Light forces them to land, and once grounded, they are vulnerable to fatal injuries, vehicle collisions or predators. Here, I review the current state of knowledge of seabird mortality induced by light pollution to identify information gaps and propose measures to address the problem. Specifically, I focus on 1) what have we learned after more than 40 years rescuing birds on archipelagos around the world; and 2) what we should know to assess and mitigate this emerging source of mortality. More than 56 species, more than one-third of them threatened, are subject to grounding by lights worldwide. Rescue programmes of grounded birds are the most relevant and extended measures to mitigate light-induced mortality, despite being a palliative action. Thanks to rescue campaigns, around 90% of collected birds are released into the wild. However, this figure seems overestimated as many grounded birds are never found or reported, being 60% a more accurate estimate. Why seabirds are attracted and grounded by lights is still poorly understood. The main body of knowledge comes from rescue programmes typically conducted by volunteers and citizen, thus information is strongly biased and fragmented, and leads to inaccurate impact estimates. More research is needed to understand and finally propose actions to mitigate light-induced mortality. Briefly, the most urgent actions are: 1) estimation of mortality and population effects; 2) assessment of threshold light levels and safe distances to pollution sources; 3) assessment of the fate of rescued birds; 4) improvement of rescue campaigns; and 5) research on and development of seabird-friendly lights to minimise attraction. In lines with these actions, I will present some unpublished results of my research to illustrate how we proceed and advance to reduce light pollution effects on seabirds.

**Authors:**

Airam Rodriguez¹

¹Estacion Biologica de Doñana CSIC

What we know and what we should know to mitigate seabird mortality induced by light pollution

**Abstract:**

Threatened species recovery is made challenging by a lack of clarity in the problems to be solved by groups of stakeholders, their competing management objectives and the diverse management alternatives that might be proposed. These factors are compounded by uncertain outcomes of interventions in data-poor species. Structured Decision Making (SDM) is a powerful process that works through these challenges, providing a framework to use appropriate scientific tools and allowing managers to make the best choice. Whilst SDM is widely used in resource management, its application to species recovery is rare. We used SDM to assist the Tara iti Recovery Group to develop a recovery plan for New Zealand's (NZ) rarest breeding bird. Tara iti, or NZ fairy tern (Sternula nereis davisae), has approximately 10-12 breeding pairs with little population growth over the last decade and no clear direction in what to do to promote population recovery. Working with multiple stakeholders, including the decision makers of NZ government and Māori (NZ's indigenous people), we identified fundamental objectives and a range of management alternatives. Using available data and expert elicitation, we predicted the consequences of each alternative on each objective, including building a set of stage-based population projection models. We addressed the biological uncertainty around novel alternative solutions, particularly for tern species, such as captive rearing and reintroduction, and compared these to more conventional field management alternatives. We then solved the optimal choice based on the decision-makers' values and risk attitudes. My research demonstrates how SDM provided a platform for all voices to be heard, and how its values-led approach is key to robust decision making for conservation of threatened species.

**Authors:**

Thalassa McMurdo Hamilton¹, Stefano Canessa², John Ewen³

¹Institute of Zoology, ZSL; UCL, ²University of Ghent, ³Institute of Zoology, ZSL

A structured approach to recovery planning for NZ's rarest breeding seabird

**Abstract:**

Rocas Atoll (3°52′S 33°49′W) is the only atoll in the South Atlantic Ocean, located approximately 260 km off the Northeast coast of Brazil. Despite its small surface (two islets with a combined area of 0.36 km2), Rocas Atoll is home to approximately 150,000 seabirds. Five species breed on the atoll: Black Noddy (Anous minutus), Brown Noddy (Anous stolidus), Sooty Tern (Onychoprion fuscatus), Masked Booby (Sula dactylatra), and Brown Booby (Sula leucogaster). Additionally, small numbers of Red-footed Booby (Sula sula) and Magnificent Frigatebird (Fregata magnificens) also roost on the islets. In June 2017, blood was collected from the tarsus (Suliformes) or jugular vein (Charadriiformes) of 214 seabirds: 26 A. minutus, 42 A. stolidus, 46 O. fuscatus, 33 S. dactylatra, 27 S. leucogaster, 20 S. sula, and 20 F. magnificens. Thin blood smears were freshly prepared, fixed with methanol, stained with Rosenfeld-Giemsa, and examined under the microscope. Two blood parasites were detected: Babesia sp. in Brown Booby (prevalence = 44%) and Haemoproteus sp. in Magnificent Frigatebird (prevalence = 10%). Although a previous study had detected DNA of Haemoproteus sp. in the blood of Brown Noddy, this parasite was not seen in this species' blood smears. Leukocyte profiles were generally similar across species and age groups, with the following averages (mean ± S.D.): heterophils 40.3%±15.9%, lymphocytes 53.8%±15.9%, monocytes 4.2%±3.9%, eosinophils 1.7%±3.0%, and basophils 0%±0.1%. The proportion of eosinophils was highest in S. dactylatra and S. leucogaster, especially in adults, suggesting a higher exposure to helminth parasites. The heterophil-to-leucocyte ratio, an indicative of physiological stress, was higher in adults than in chicks and immatures in most species, with the exception of A. stolidus where an opposite pattern was noted. This is the first hematological study of seabirds at Rocas Atoll, and is part of a broader health survey program that aims to identify pathogens and health challenges that may bear significance for seabird conservation at Brazil's oceanic islands.

**Authors:**

Ralph Vanstreels¹, Daniela Mariani², Renata Hurtado¹, Veridiana Galizia³, Maurizélia Silva⁴, Jean Ramos Silva²

¹Institute of Research and Rehabilitation of Marine Animals, ²Universidade Federal Rural de Pernambuco, ³Autonomous veterinarian, ⁴Instituto Chico Mendes de Conservação da Biodiversidade

Hematology and blood parasites of seabirds at Rocas Atoll, Brazil

**Abstract:**

Interactions with fisheries have strong effects on seabird ecology, behaviour and demography. These effects may be direct or indirect, and either negative (e.g. bycatch, food depletion) or positive (e.g. food provisioning via discards and offal). Albatrosses and petrels are the most threatened group of seabirds and highly attracted to fishing vessels. Their high dispersion capacity results in interactions with fleets from several countries, including in the high seas. Strong interactions are expected where the overlap between fisheries and seabird foraging grounds is high, like in the Southwest Atlantic Ocean. Here, we described and quantified the assemblage of albatrosses and petrels attending pelagic longline (PLL) vessels off southern Brazil. Data was collected by on-board observers taken voluntarily by fishermen, totalizing 927 fishing sets (2002-2018), distributed between latitude 25º?36º S and longitude 53º?29º W. For each set, seabird censuses were conducted during hauling and environmental data was obtained. A total of 37 species of 15 genera were recorded attending PLL vessels, and abundance and species composition varied seasonally. Abundance was higher during austral Autumn/Winter, when Antarctic/Subantarctic and Tristan/Gough breeders accounted for 52% and 46% of the records, respectively, while during Spring/Summer, Antarctic/Subantarctic and Tristan/Gough breeders represented 23% and 74% of the abundance, respectively. Spectacled petrel and Atlantic Yellow-nosed Albatross were the two most frequent species in both seasons, and Spectacled petrels were also the most abundant taxa year-round, suggesting this area is important for both species during breeding and non-breeding periods. The second most abundant were Black-browed Albatross and Great Shearwater, for Autumn/Winter and Spring/Summer, respectively. The assemblage of albatrosses and petrels associated with PLL fisheries off southern Brazil is rich, varies seasonally, and is largely dominated by Mid-South Atlantic and Subantarctic breeders and North Atlantic migrants, which are subject to both positive and negative effects of this interaction.

**Authors:**

Gabriel Canani¹, Augusto Silva Costa¹, Tatiana S. Neves¹, Dimas Gianuca¹

¹Projeto Albatroz

Seabird assemblage associated with pelagic longline fisheries off southern Brazil

**Abstract:**

Following the competitive exclusion principle, two closely-related species living in sympatry can only coexist if ecological niche partitioning occurs. Throughout their distribution range, Imperial Cormorant (Leucocarbo atriceps) and Rock Shag (L. magellanicus) often breed in mixed-species colonies in Patagonia, Argentina. Isotopic niche assessment of both species was performed during two breeding seasons (2010/11 and 2011/12) in three different colonies were they breed syntopically. The three colonies, Isla Gran Robredo (45°07'54''S, 66°03'40''W), Isla Leones (45°03'28''S, 65°35'08''W), and Isla Viana (45°11'27''S, 63°23'50''W), are located within the 'Patagonia Austral Marine Park'. Whole blood samples were obtained simultaneously from breeding adults of both species during the early chick stage and used for stable isotope analysis. Isotopic niche was described by means of centroid analysis and Bayesian ellipse-based metrics. The isotopic niche overlap between species was in general small or insignificant, suggesting niche partitioning, and the isotopic niche width in the different colonies and seasons was significantly smaller in the Imperial Cormorant than in the Rock Shag. However, the isotopic niche of the Imperial Cormorant in Isla Viana during the second study season was totally included in the isotopic niche of the Rock Shag, suggesting an important niche overlap. Results showed evidence that niche partitioning processes in these cormorants is context dependent. However, further studies are needed including independent measures of prey availability and niche evaluation at additional colonies where these species breed alone and with other cormorant species, considering that the metacommunity framework predicts that the combination of species in metapopulation contexts could be sometimes achieved through pairs of species with similar resource utilization.

**Authors:**

Alejandro Gatto¹, Pablo Yorio¹

¹Centro Nacional Patagónico (CENPAT) - CONICET

Evaluating the coexistence of Imperial Cormorant and Rock Shag through isotopic niches at different colonies in central Patagonia, Argentina

**Abstract:**

Sexual size dimorphism in seabirds may reduce intraspecific food competition through the exploitation of different trophic niches by each sex. We tested the intraspecific trophic segregation between sexes of Brown Booby (Sula leucogaster) using stable isotopes (δ15N and δ13C) from whole blood and regurgitated prey. As females are larger and heavier than males, it is expected that females have a broader niche amplitude and higher trophic position compared to males, due to the consumption of a wider variety of prey sizes. The studied population of Brown Booby breeds in Santana Archipelago (SA), located 8 km from the coast of Macaé municipality, in north of Rio de Janeiro State, Brazil. Commercial fishing is conducted around the SA mainly by gillnets and bottom trawlers, which provides discards, as demersal fishes, generally inaccessible to birds. Expeditions to the SA occurred from June 2017 to May 2018. It were sampled 84 females and 56 males, and 54 regurgitates. Twenty-four species were identified from 399 prey items. The Relative Importance Index indicated the pelagic Dogtooth herring (Chirocentrodon bleekerianus) as the most important prey for females and the demersal Stripped weakfish (Cynoscion guatucupa) for males. Demersal fishes were predominantly consumed than pelagic fishes along throughout the seasons, mainly during winter (85% of the diet), indicating the importance of the fishing activity in this seabird diet. δ15N and δ13C differed between sex in all seasons, mainly due the δ13C values, which indicates that females and males forage different proportions of demersal fishes, as showed by the regurgitates. Trophic position (δ15N) did not differ between sexes, indicating that birds may be consuming different prey with similar trophic position. Females had broader isotopic niche than males in all seasons. Brown Booby population from the Santana Archipelago is trophically segregated between sexes and fish discards are an important part of the seabird diet, which helps to promote the niche segregation.

**Authors:**

Emília Valim¹, Arthur Bauer¹, Luciano Fischer¹, Patricia Mancini¹

¹Universidade Federal do Rio de Janeiro (UFRJ)

Trophic segregation in Brown Booby (Sula leucogaster) drive by fishing activities in a coastal archipelago in the Southwestern Atlantic Ocean.

**Abstract:**

Given a predator's imperfect knowledge of prey distribution, predators often use environmental or biological cues as proxies to increase the probability of encountering prey patches, especially under low productivity conditions. Predator-habitat associations can be used for many applications, such as targeted surveys, distribution models, and marine spatial planning. However, little is known about habitat associations for seabirds and marine mammals during low productivity winter periods in temperate latitudes due to few winter at-sea surveys. In this study, we aimed to quantify marine predator assemblages and their habitat associations during the winter downwelling season (i.e. low productivity) of the northern California Current. Marine bird and mammal counts were continuously collected during systematic at-sea surveys during February-March in the northern California Current across four years (2006, 2008, 2009, and 2012). The ten most commonly sighted seabird species (e.g., piscivorous alcids, primarily common murres Uria aalge; planktivorous alcids, primarily cassin's auklet Ptychoramphus aleuticus), were binned by 1-km. As marine mammals were orders of magnitude less abundant than birds, we used all marine mammal sightings without binning. We examined seabird and marine mammal distributions in relation to seven in-situ and remotely-sensed habitat characteristics (e.g., depth, distance from shore, sea surface temperature). As survey data often do not meet the assumptions of parametric statistics and transformations can reduce precision, we used a non-parametric multivariate analysis (e.g. canonical correspondence analysis (CCA)) to quantify species associations and habitat associations. Given the assumption that food resources are scarce during winter in the northern California Current because underlying primary production in winter is light-limited, we predict that despite differences in foraging ecology, predators will show similar habitat associations. Results will begin to address a key knowledge gap in the northern California Current ecosystem function by identifying habitat features likely to be associated with prey patchiness and hence support energy flow to upper trophic levels during winter downwelling.

**Authors:**

Laura Bliss¹, Jeannette Zamon², Gail Davoren¹, Brad Hanson³, Dawn Noren³, Candice Emmons³, Marla Holt³

¹University of Manitoba, ²Northwest Fisheries Science Center, NOAA Fisheries, ³NOAA NMFS Northwest Fisheries Science Center

Winter habitat associations of marine predators in the northern California Current

**Abstract:**

Migration is common throughout the animal kingdom, while individuals often move to areas of high productivity, travelling long distances can be costly. Hence, the migration season can influence individual fitness as it is key in acquiring the energy required for reproduction. Recent studies have highlighted the important interaction between migration and breeding behaviour and identified so called ?carry-over? effects where behaviour in one period affects the behaviour in the other. In this study, we examine the foraging effort of Wandering albatrosses (Diomedea exulans) during migration and breeding to determine their effect on fitness. Using seven years of tracking data from a population on the Crozet Islands we examined the importance of age and sex on foraging effort (i.e. flight duration and take-offs). We found the foraging effort was greater for females and decreased with age. Past reproductive successes had an influence on the foraging effort during migration, which subsequently had an effect on the reproductive successes in the next breeding season. Birds with lower energetic costs before the breeding season were more successful breeders. Overall, the breeding season was more costly. This study highlights the importance of linking both seasons when trying to understand the life-history of the wandering albatross.

**Authors:**

Milena Cairo¹, Samantha Patrick¹, Henri Weimerskirch²

¹University of Liverpool, ²Centre d'Etudes Biologiques de Chizé, CNRS;Université de La Rochelle

The foraging effort of the Wandering albatross (Diomedea exulans) during breeding and migration seasons

**Abstract:**

Seasonal and annual climate variation is linked to fluctuations in resource abundance and/or distribution. In adverse conditions, animals with flexible foraging behaviours are more likely to find enough of these resources to sustain both self-maintenance and reproduction. In light of rapid habitat changes due to global warming and habitat degradation, plasticity in foraging behaviour has important implications for population trajectories. Here, the foraging behaviour of four sub-Antarctic albatross species was investigated from 2015/16 to 2017/18, a period that was characterized by pronounced climatic variability. Over three breeding seasons on Marion Island, GPS dataloggers were deployed on incubating wandering (WA), grey-headed (GHA), sooty (SA) and light-mantled (LMA) albatrosses to track there at-sea distribution. The response of birds to environmental variability was investigated by quantifying changes in their foraging behaviour along two axes: spatial distribution, using kernel density analysis, and foraging habitat, using generalised additive models and Bayesian mixed models. Our results suggest that during incubation, the albatross species have different foraging strategies and levels behavioural flexibility when responding to environmental variability. The WA appear as foraging habitat generalist, with individuals foraging in different habitats during a foraging trip. In contrast, the three smaller albatrosses exhibited interannual differences in foraging habitats. The generalist habitat-use of the WAB and differential habitat use of the GHA, DMA and LMA suggests that these species might be resilient to predicted changes in climate. Future investigations of marine predator response to environmental variability are likely to benefit from coupling information on foraging behaviour with demographics. This will allow for better understanding of the link between behavioural plasticity and population responses.

**Authors:**

Tegan Carpenter-Kling¹, Ryan Reisinger², Florian Orgeret¹, Maelle Connan¹, Pierre Pistorius¹

¹Marine Apex Predator Research Unit (MAPRU), Institute for Coastal and Marine Research, FitzPatrick I, ²Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-La Rochelle Université

Sustainable fisheries for seabirds: Defining prey density thresholds through a combination of bio-energetic modeling, bio-logging and an unmanned surface vessel

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