United States

**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&#39;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&#39;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&#39; 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

3rd World Seabird Conference

A structured approach to recovery planning for NZ&#39;s rarest breeding seabird

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:**

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

technical paper

**Abstract:**

Despite its isolation and extreme climate, Antarctica is home to a diversity of fauna and associated microorganisms, including viruses, parasites, and even antimicrobial-resistant bacteria. It has previously been proposed that perhaps the most iconic Antarctic animal, the penguin, experiences low pathogen pressure, accounting for their susceptibility to disease when exposed to foreign environments. Climate-driven and anthropogenically assisted virus emergence in Antarctica is therefore of considerable concern. At present, however, there is little understanding of the diversity and abundance of viruses currently found in Antarctica, the ecological factors that shape this diversity, nor how it relates to that seen in other geographic regions. As a means to test the hypothesis of low pathogen pressure, we determined the viromes of three species of penguins and their ticks sampled on the Antarctic peninsula: Adélie penguins (Pygoscelis adeliae), Chinstrap penguins (Pygoscelis antarctica) and Gentoo penguins (Pygoscelis papua) and the seabird tick (Ixodes uriae). Using total RNA-Sequencing (meta-transcriptomics) we identified 107 viral species, comprising penguin viruses (n=18), penguin diet and microbiome associated viruses (n=82), tick viruses (n=4) and tick transmitted arboviruses (n=2), with Adélie and Chinstrap penguins harbouring more virome diversity than Gentoo penguins. Strikingly, the level of virome diversity revealed in penguins is comparable to that see in Australian shorebirds and ducks, including the detection of many of the same viral families, and rejects the notion that penguins are subject to lower pathogen pressure. Furthermore, through the detection of previously detected viruses in penguins (Influenza A virus and Avian Avulavirus 17) we suggest that Antarctic penguins are not only spill-over hosts, but key reservoir hosts for viruses, including a number of arthropod-borne viruses (Gavier and Fennes virus). We suggest that additional sampling and continued improvement of sampling strategies will reveal an increasing diversity of viruses in Antarctic wildlife.

**Authors:**

Michelle Wille¹, Michelle Wille², Mang Shi², Daniel Gonzalez-Acuna³, Edward Holmes², Aeron Hurt¹

¹WHO Collaborating Centre for Reference and Research on Influenza, ²Marie Bashir Institute for Infectious Diseases, University of Sydney, ³Universidad de Concepcion, Facultad de Ciencias Veterinarias

Substantial viral diversity in Antarctic penguins and their ticks: no evidence for low pathogen pressure

**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:**

Changes in foraging strategies throughout the year are key determinants of seabird population dynamics. However, due to seabird post-breeding dispersal, year-round trophic ecology studies rarely focus on individuals from known colonies. Using stable isotope analysis (δ15N, δ13C) of blood and primary feathers, we tested during 2012 the trophic niche variation throughout the year in Kelp Gulls Larus dominicanus from three colonies in Patagonia, Argentina, located in areas with different availability of anthropogenic food subsidies. Isotopic niche width, measured using multivariate ellipse-based metrics, was wider at all colonies during the non-breeding season, suggesting that during this period gulls forage on a greater variety of food sources possibly related to post-breeding dispersal, seasonal changes in food resources, and/or the relaxation of central place foraging. Individuals from the colony with year-round availability of fisheries discards (Isla Vernaci) presented the lower isotopic niche width year-round compared to those from the other two colonies, one with discards only available during the breeding season (Punta Tombo) and the other with only open-air refuse dumps available all year-round (Punta León). At Isla Vernaci, an abrupt expansion in niche width occurred later in the non-breeding season, after the start of a fisheries moratorium, suggesting that Kelp Gulls remained in nearby areas and partly associated to trawl fisheries between breeding events. Preliminary diet results indicate that most studied individuals from Isla Vernaci were feeding on demersal prey, only available from fisheries discards as Kelp Gulls are surface feeders. These results suggest that the availability of discards can greatly influence Kelp Gull foraging strategies and non-breeding movements, and that changes in niche metrics can be context dependent. Future studies should complement the assessment of niche variability with studies of diet composition throughout the year.

**Authors:**

Nora Lisnizer¹, Alejandro Gatto¹, Pablo Yorio¹

¹Consejo Nacional de Investigaciones Científicas y Técnicas

Trophic niche variation throughout the year in the opportunistic Kelp Gull at different trophic scenarios in Patagonia, Argentina

**Abstract:**

Knowledge of sexual differences in diet composition is key to properly understand aspects of seabird life history, their role in marine food webs, and how human activities such as fisheries may differentially affect individuals of each sex. We assessed differences in diet composition between male and female Imperial Cormorants (<i>Leucocarbo atriceps</i>) breeding at Islas Blancas (44°46´S, 65°39´W), Argentina. Imperial cormorants show sexual size dimorphism, with males being 18% heavier than females. We obtained stomach samples through induced regurgitation from 60 adult individuals, 10 of each sex during three stages of the breeding cycle (incubation, small chicks and large chicks) in 2019. At least 11 and 28 prey taxa were recorded in stomach samples of males and females, respectively. Females consumed a greater diversity of prey species and a significantly higher number of prey items per stomach content. A two-way crossed analysis of similarities showed significant sex differences in diet composition in terms of numerical frequency along the breeding cycle. Males mainly consumed demersal species, with Argentine Red Shrimp Pleoticus muelleri (43.6%) and Argentine Hake Merluccius hubbsi (35.9%) being the main prey during incubation, and hake (>77%) the dominant prey during both chick rearing stages. Females preyed upon benthic species mostly inhabiting rocky reefs. Prey with higher representation in the diet in the three stages analyzed were the fishes Patagonotothen spp. (30.84%, 36.43% and 19.37%). Results show a clear sexual segregation in the diet of Imperial Cormorants, in agreement with studies in other dimorphic seabirds, and also suggest that sex differences reflect the spatial segregation in feeding behavior of male and female individuals. Males and females may be playing different roles in coastal food webs and may be differentially affected by coastal trawl fisheries as hake and shrimp are their main target species.

**Authors:**

Cynthia Ibarra¹, Nicolás Suárez¹, Juan Ignacio Cortés¹, Ximena Navoa², Cristian Silva³, Pablo Yorio¹

¹Centro para el Estudio de Sistemas Marinos - CONICET, ²UNPSJB- Instituto de Investigación de Hidrobiología, ³Universidad Nacional de la Patagonia San Juan Bosco

Sexual segregation in the diet of the dimorphic Imperial Cormorant breeding in northern Argentine Patagonia

**Abstract:**

While many members of the Larus genus have adapted to urban environments, the degree to which urban environments are utilized for foraging may vary greatly between species. To understand how the use of urban areas drives movement and foraging behavior in gulls, we compared differences in the habitat use and foraging ecology of herring gulls (Larus argentatus; HERG) and the lesser studied great black-backed gull (Larus marinus; GBBG). HERG are widely known to utilize urban environments, but evidence suggests that GBBG may primarily forage in marine environments. We collected data from a mixed-species breeding colony on Young's Island, NY, during the incubation period in spring 2019. We deployed GPS tags on 6 GBBG and 3 HERG with minimum and maximum deployment durations of 5 and12 days, respectively. Locations of foraging behavior were identified as areas of restricted search (ARS) using First Passage Time (FPT) analysis. We found that the proportion of foraging points within urban environments was significantly lower for GBBG than for HERG (Wilcoxon, p=0.01962). Site fidelity and the average number of foraging trips per day were also significantly lower for GBBG than HERG (Wilcoxon, p=0.03887; p=0.0181). Our results exemplify the variation in urban adaptability that exists within the Larus genus and how urban vs. non-urban habitat use may influence foraging behavior. Ongoing work is using bulk stable isotope analyses of whole blood examining ẟ13C and ẟ15N values for tagged individuals to assess differences in isotopic signatures in relation to habitat use. Together, these analyses will provide further insight in to how habitat use and the use of urban environments impacts behavior, diet, and trophic ecology.

**Authors:**

Kimberly Lato¹, Eleanor Heywood¹, Richard Veit², Lesley Thorne¹

¹Stony Brook University, ²College of Staten Island

Comparing the habitat use and foraging ecology of great black-backed and herring gulls

**Abstract:**

Fishing activities provide marine scavengers with large quantities of fisheries discards, and this anthropogenic food subsidy has become a key component in the trophic ecology of seabirds worldwide. Seabirds determine through their selective consumption which components of the discard fraction are made available to scavenger organisms in the water column and on the seabed. We evaluated the selective consumption of discards by seabirds associated with a coastal fishery targeting Argentine Red Shrimp (Pleoticus muelleri) in Patagonia, Argentina. The fishery consisting of 42 vessels discarded a mean of 682 kg per haul (n = 113). A total of 65 species were discarded, and Argentine Hake (Merluccius hubbsi) (96% FO; 260 kg/haul) and Argentine Red Shrimp (100% FO; 195 kg/haul) dominated the discard fraction of the catch. The Kelp Gull (Larus dominicanus) and Black-browed Albatross (Thalassarche melanophris) were present in all hauls and were the most abundant of the seven seabird species scavenging behind vessels (171 ± 110 and 57 ± 52 individuals per haul, respectively) representing together more than 93.5% of birds in associated assemblages. A total of 29 prey items were experimentally discarded (n = 1392), nine of which were totally ignored. Ignored invertebrates included tunicates, which constitute a large fraction of discards (>100 kg/haul). Mean sizes of fish and invertebrates consumed were 22.5 ± 8.6 and 10.4 ± 7.8 cm, respectively. Kelp Gulls selected significantly smaller prey than Black-browed Albatrosses (16.3 ± 7.9 and 29.1 ± 8.1 cm, respectively; P<0.001), showing partitioning of prey resources. Results indicate that all discarded fish species, but not all sizes, were consumed by seabirds, and some of the most abundant discarded invertebrates were ignored. Thus, only a fraction of fish and mostly invertebrates would remain available for scavenging organisms in the water column and benthic habitats.

**Authors:**

Cristian Marinao¹, Pablo Yorio²

¹Centro de Estudio de Sistemas Marinos, CESIMAR-CONICET, Argentina, ²Centro de Estudio de Sistemas Marinos, CESIMAR-CONICET, Argentina and Wildlife Conservation Society

Scavenging seabirds and selective consumption of discards in a coastal shrimp trawl fishery in Patagonia, Argentina

**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

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

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

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