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Martin Beal, Maria P. Dias, Richard A. Phillips, Steffen Oppel, Carolina Hazin, Elizabeth J. Pearmain, Josh Adams, David J. Anderson, Michelle Antolos, Javier A. Arata, José Manuel Arcos, John P. Y. Arnould, Jill Awkerman, Elizabeth Bell, Mike Bell, Mark Carey, Ryan Carle, Thomas A. Clay, Jaimie Cleeland, Valentina Colodro, Melinda Conners, Marta Cruz-Flores, Richard Cuthbert, Karine Delord, Lorna Deppe, Ben J. Dilley, Herculano Dinis, Graeme Elliott, Fernanda De Felipe, Jonathan Felis, Manuela G. Forero, Amanda Freeman, Akira Fukuda, Jacob González-Solís, José Pedro Granadeiro, April Hedd, Peter Hodum, José Manuel Igual, Audrey Jaeger, Todd J. Landers, Matthieu Le Corre, Azwianewi Makhado, Benjamin Metzger, Teresa Militão, William A. Montevecchi, Virginia Morera-Pujol, Leia Navarro-Herrero, Deon Nel, David Nicholls, Daniel Oro, Ridha Ouni, Kiyoaki Ozaki, Flavio Quintana, Raül Ramos, Tim Reid, José Manuel Reyes-González, Christopher Robertson, Graham Robertson, Mohamed Salah Romdhane, Peter G. Ryan, Paul Sagar, Fumio Sato, Stefan Schoombie, R. Paul Scofield, Scott A. Shaffer, Nirmal Jivan Shah, Kim L. Stevens, Christopher Surman, Robert M. Suryan, Akinori Takahashi, Vikash Tatayah, Graeme Taylor, David R. Thompson, Leigh Torres, Kath Walker, Ross Wanless, Susan M. Waugh, Henri Weimerskirch, Takashi Yamamoto, Zuzana Zajkova, Laura Zango, Paulo Catry. (2021). Global political responsibility for the conservation of albatrosses and large petrels (Vol. 7).
Abstract: Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm.
Programme: 109
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Aymeric Fromant, Karine Delord, Charles-André Bost, Yonina H. Eizenberg, Jonathan A. Botha, Yves Cherel, Paco Bustamante, Brett R. Gardner, Maud Brault-Favrou, Arnaud Lec'hvien, John P. Y. Arnould. (2021). Impact of extreme environmental conditions: Foraging behaviour and trophic ecology responses of a diving seabird, the common diving petrel (Vol. 198).
Abstract: The reproductive success of birds is strongly driven by environmental conditions at different time scales. Thus, during periods of low food availability, breeding success is constrained by the ability of adults to adapt their foraging effort and feeding behaviour to maintain regular incubation shifts and chick provisioning. However, while large seabirds can buffer disruptions in prey availability, the ecophysiological constraints of smaller species may limit their behavioural flexibility. By combining information on at-sea movements, foraging habitat, trophic niche, and breeding success, this study evaluated the effects of intense variability in oceanographic conditions on common diving petrels (Pelecanoides urinatrix) at the northern extent of their range in south-eastern Australia during four consecutive breeding seasons. Unusually low breeding success (6 and 0%) was observed during two years with intense heatwave events, which were associated with higher foraging effort (foraging trips twice longer) and a substantial shift in trophic niche (lower blood δ15N values). These findings suggest that common diving petrels in Bass Strait may have reached a critical threshold above which buffering the effects of environmental variability on their reproductive output is not possible. The clear cascading impacts that marine heatwaves have on zooplankton feeders illustrate the profound bottom-up effect induced by such extreme environmental variations, and suggest strong impact on higher-trophic levels. The wide, circumpolar breeding distribution of the common diving petrel, and its high sensitivity to variations in oceanographic conditions, suggest that this species may be a suitable model to study short-term and long-term behavioural responses to the effects of climate change throughout the Southern Ocean.
Keywords: GPS tracking Habitat modelling Inter-annual variation Marine heatwave Stable isotopes
Programme: 109
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Paul Tixier, Nicolas Gasco, Jared R. Towers, Christophe Guinet. (2021). Killer whales of the Crozet Archipelago and adjacent waters: photo-identification catalogue, population status and distribution in 2020.
Abstract: Three 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 opportunistically photo-identified around the Crozet archipelago since the 1960s. Together with photo-identification data collected in the Prince Edward/Marion EEZ, Kerguelen EEZ and international waters, this report provides up to date information on the abundance and distribution of the Crozet killer whales. In total, 124,313 photographs taken during 2,109 encounters since 1964 were analysed, allowing for 299 individuals to be identified. Most encounters with available data were from the Crozet EEZ (1,432 from longliners, 602 from Île de la Possession) and occurred after 2003 when photo-identification was implemented in the fishery observer program. Among the 188 individuals recorded in the Crozet EEZ since 2003, 22 (12%) were also photographed in the Kerguelen EEZ, 13 (7%) in the Prince Edward/Marion EEZ and 13 (7%) in adjacent international waters. The frequently encountered subset of the Crozet killer whale population was composed of 23 social units (maternal groups), 19 of which included individuals alive in 2020. These social units ranged in size from 1 to 11 individuals with a mean (± SD) of 4 ± 3 per unit. As of June 2020 when the latest photographs included in the study were taken, abundance of this subset was 89-94 individuals. However, detailed analysis of data collected between 2005 and 2020 shows that the number of confirmed deaths (n = 51) exceeds the number of recorded births (n = 46), resulting in a 5% decrease of the population size over this period. These deaths were distributed across the population with the majority occurring in the most common sex and age classes – adult females and juveniles. Factors contributing to mortalities are unclear, but may include lethal interactions with illegal fisheries. When paired with the fact that the Crozet killer whales already underwent a severe mortality episode in the 1990s, these findings raise strong concerns about the future of the population and stress the necessity of conservation actions while maintaining an intensive monitoring effort.
Programme: 109
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Alberto Baudena, Enrico Ser-Giacomi, Donatella D’Onofrio, Xavier Capet, Cedric Cotté, Yves Cherel, Francesco D’Ovidio. (2021). Fine-scale structures as spots of increased fish concentration in the open ocean (Vol. 11).
Abstract: Oceanic frontal zones have been shown to deeply influence the distribution of primary producers and, at the other extreme of the trophic web, top predators. However, the relationship between these structures and intermediate trophic levels is much more obscure. In this paper we address this knowledge gap by comparing acoustic measurements of mesopelagic fish concentrations to satellite-derived fine-scale Lagrangian Coherent Structures in the Indian sector of the Southern Ocean. First, we demonstrate that higher fish concentrations occur more frequently in correspondence with strong Lagrangian Coherent Structures. Secondly, we illustrate that, while increased fish densities are more likely to be observed over these structures, the presence of a fine-scale feature does not imply a concomitant fish accumulation, as other factors affect fish distribution. Thirdly, we show that, when only chlorophyll-rich waters are considered, front intensity modulates significantly more the local fish concentration. Finally, we discuss a model representing fish movement along Lagrangian features, specifically built for mid-trophic levels. Its results, obtained with realistic parameters, are qualitatively consistent with the observations and the spatio-temporal scales analysed. Overall, these findings may help to integrate intermediate trophic levels in trophic models, which can ultimately support management and conservation policies.
Keywords: Fisheries Marine biology Physical oceanography
Programme: 109
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Casey Youngflesh, Yun Li, Heather J. Lynch, Karine Delord, Christophe Barbraud, Rubao Ji, Stephanie Jenouvrier. (2021). Lack of synchronized breeding success in a seabird community: extreme events, niche separation, and environmental variability (Vol. 130).
Abstract: Synchrony in ecological systems, the degree to which elements respond similarly over time or space, can inform our understanding of how ecosystems function and how they are responding to global change. While studies of ecological synchrony are often focused on within-species dynamics, synchrony among species may provide important insights into how dynamics of one species are indicative of conditions relevant to the larger community, with both basic and applied implications. Ecological theory suggests there may be conditions under which communities might exhibit increased synchrony, however, the degree to which these patterns are borne out in natural systems is currently unknown. We used long-term breeding success data from a community of Antarctic seabirds to assess the degree of interspecific, community synchrony, and the role that extreme events play in driving these dynamics. We assessed theoretical links between community synchrony, niche separation, and environmental variability using data from this and three other seabird communities as well as a simulation study. Results show that reproductive success for individual species in the Antarctic seabird community fluctuated relatively independently from one another, resulting in little synchrony across this community, outside of extreme years. While an exceptionally poor year for a given species was not necessarily associated with an exceptionally poor year for any other species, one community-wide extreme year existed. When compared to other seabird communities, this group of Antarctic seabirds exhibited lower overall synchrony and higher estimated niche separation, supporting theoretical predictions. Empirical and simulation-derived results suggest that communities where temporal variation is small for conditions in which species respond substantially differently, and large for conditions in which species respond similarly, may exhibit more synchronous dynamics. Identifying where and why synchronous dynamics might be more apparent has the potential to inform how ecological communities might respond to future global change.
Keywords: Antarctica environmental indicators extreme events global change niche separation synchrony
Programme: 109
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Christophe Barbraud, Karine Delord. (2021). Selection against immigrants in wild seabird populations (Vol. 24).
Abstract: Immigration is a major demographic parameter shaping population dynamics and is an important driver of eco-evolutionary patterns, but the fitness consequences for individuals following their settlement to a new population (immigrants) remain poorly tested in wild animal populations, particularly among long-lived species. Here we show that immigrants have a lower fitness than residents in three wild seabird populations (wandering albatross Diomedea exulans, southern fulmar Fulmarus glacialoides, snow petrel Pagodroma nivea). Across all species and during a 32-year period, immigrants made on average −9 to 29% fewer breeding attempts, had 5–31% fewer fledglings, had 2–16% lower breeding success and produced 6–46% fewer recruits. Female immigration and male residency were also favored through differences in breeding performance. We provide evidence for selection against immigrants in wild populations of long-lived species and our results are consistent with female-biased dispersal in birds being driven by asymmetric limiting resources and the competitive ability of dispersers vs. non-dispersers.
Keywords: Dispersal fitness immigrant seabirds sex-biased dispersal
Programme: 109
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Alain Manceau, Romain Brossier, Sarah E. Janssen, Tylor J. Rosera, David P. Krabbenhoft, Yves Cherel, Paco Bustamante, Brett A. Poulin. (2021). Mercury Isotope Fractionation by Internal Demethylation and Biomineralization Reactions in Seabirds: Implications for Environmental Mercury Science (Vol. 55).
Abstract: A prerequisite for environmental and toxicological applications of mercury (Hg) stable isotopes in wildlife and humans is quantifying the isotopic fractionation of biological reactions. Here, we measured stable Hg isotope values of relevant tissues of giant petrels (Macronectes spp.). Isotopic data were interpreted with published HR-XANES spectroscopic data that document a stepwise transformation of methylmercury (MeHg) to Hg-tetraselenolate (Hg(Sec)4) and mercury selenide (HgSe) (Sec = selenocysteine). By mathematical inversion of isotopic and spectroscopic data, identical δ202Hg values for MeHg (2.69 ± 0.04‰), Hg(Sec)4 (−1.37 ± 0.06‰), and HgSe (0.18 ± 0.02‰) were determined in 23 tissues of eight birds from the Kerguelen Islands and Adélie Land (Antarctica). Isotopic differences in δ202Hg between MeHg and Hg(Sec)4 (−4.1 ± 0.1‰) reflect mass-dependent fractionation from a kinetic isotope effect due to the MeHg → Hg(Sec)4 demethylation reaction. Surprisingly, Hg(Sec)4 and HgSe differed isotopically in δ202Hg (+1.6 ± 0.1‰) and mass-independent anomalies (i.e., changes in Δ199Hg of ≤0.3‰), consistent with equilibrium isotope effects of mass-dependent and nuclear volume fractionation from Hg(Sec)4 → HgSe biomineralization. The invariance of species-specific δ202Hg values across tissues and individual birds reflects the kinetic lability of Hg-ligand bonds and tissue-specific redistribution of MeHg and inorganic Hg, likely as Hg(Sec)4. These observations provide fundamental information necessary to improve the interpretation of stable Hg isotope data and provoke a revisitation of processes governing isotopic fractionation in biota and toxicological risk assessment in wildlife.
Programme: 109
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Christophe Sauser, Karine Delord, Christophe Barbraud. (2021). Sea ice and local weather affect reproductive phenology of a polar seabird with breeding consequences (Vol. 123).
Abstract: Breeding at the right time is essential for animals living in seasonal environments to ensure that energy requirements for reproduction, especially the nutritional needs for rearing offspring, coincide with peak food availability. Climate change is likely to cause modifications in the timing of maximum food availability, and organisms living in polar environments where the breeding period is heavily contracted may be particularly affected. Here we used a 26-year dataset to study the phenological response of a pagophilic species, the Snow Petrel (Pagodroma nivea), to climate change and its demographic impact. First, we investigated the trends and relationships between climate variables and hatching dates measured in three neighboring colonies. In a second step, we examined the impact of the hatching date and environmental covariates on the fledging probability. Our results showed that sea ice, a climate-related variable, showed a positive temporal trend. We found that hatching date was delayed when sea ice concentration was greater and local weather conditions were worse (i.e., increase in the number of windy days or the number of snow days). Hatching date had a negative effect on fledging probability, and fledging probability showed a bell-shaped temporal trend. We suggest that Snow Petrels can delay breeding phenology in response to environmental conditions. However, this plasticity may be limited as fledging success decreased with delayed hatching, potentially making the Snow Petrel vulnerable to a mismatch between resource availability and nutritional needs.• Timing of reproduction is essential for wild animals to ensure that reproductive requirements, including nutritional requirements for rearing offspring, coincide with peak food availability.• Climate change can affect the timing of food availability, and organisms living in polar environments, where the timing of reproduction is highly contracted, may be particularly affected. We analyzed whether a sea ice dependent species, the Snow Petrel (Pagodroma nivea), would breed earlier or later in response to climate change, as measured by changes in sea ice and weather conditions. Then, we looked at the impact that a shift in reproduction might have on breeding success.• Our results showed that hatching date was delayed when sea ice increased and local weather conditions worsened. Secondly, we showed that the shift in hatching date had a negative effect on breeding success.• Snow Petrels adjusted the onset of reproduction in response to environmental changes. However, this adjustment had limits since late reproduction likely leads to a mismatch between the availability of resources and nutritional needs, and thus to a decrease the breeding success.
Programme: 109
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Denis Réale. (2021). Sexual segregation in a sexually dimorphic seabird: a matter of spatial scale (Vol. 1).
Abstract: A recommendation of: Christophe Barbraud, Karine Delord, Akiko Kato, Paco Bustamante, Yves Cherel Sexual segregation in a highly pagophilic and sexually dimorphic marine predator https://doi.org/10.1101/472431
Programme: 109
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Aurore Ponchon, Amandine Gamble, Jérémy Tornos, Karine Delord, Christophe Barbraud, Justin M. J. Travis, Henri Weimerskirch, Thierry Boulinier. (2021). Similar at-sea behaviour but different habitat use between failed and successful breeding albatrosses (Vol. 678).
Abstract: Breeding failure is expected to induce behavioural changes in central place foragers. Indeed, after a failed reproductive attempt, breeding individuals are relieved from having to return to their breeding site for reproductive duties and thus are less constrained than successful breeders in their movements during the remainder of the breeding season. Accordingly, they are expected to adjust their behaviour, travelling longer in distance and/or time to reach foraging grounds. They are also expected to use different foraging areas to decrease local intra-specific competition with successful breeders. We compared the at-sea behaviour and habitat use of successful and failed Indian yellow-nosed albatrosses nesting in Amsterdam Island, Southern Indian Ocean, during 2 chick-rearing seasons. Failed breeders exhibited the same at-sea foraging behaviour, travelling as far and as long as successful breeders. They also spent the same amount of time on their nest between at-sea trips. Nevertheless, habitat models revealed partial spatial segregation of failed breeders, which used specific foraging areas characterized by deeper and colder waters in addition to the areas they shared with successful breeders. Our study shows the importance of combining a range of analytical methods (spatial analysis, behavioural inferences with advanced movement models and habitat models) to infer the at-sea behaviour and habitat use of seabirds. It also stresses the importance of considering individual breeding status when aiming to understand the spatial distribution of individuals, especially when this information may have conservation implications.
Keywords: Behavioural state Breeding failure Foraging behaviour Habitat models Inter-individual variability Procellariiformes Thalassarche carteri
Programme: 109
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