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| Thiebault, Andrea; Pistorius, Pierre; Mullers, Ralf; Tremblay, Yann. |
| Most seabirds are very noisy at their breeding colonies, when aggregated in high densities. Calls are used for individual recognition and also emitted during agonistic interactions. When at sea, many seabirds aggregate over patchily distributed resources and may benefit from foraging in groups. Because these aggregations are so common, it raises the question of whether seabirds use acoustic communication when foraging at sea? We deployed video-cameras with built in microphones on 36 Cape gannets (Morus capensis) during the breeding season of 2010-2011 at Bird Island (Algoa Bay, South Africa) to study their foraging behaviour and vocal activity at sea. Group formation was derived from the camera footage. During similar to 42 h, calls were recorded on 72... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00625/73757/74429.pdf |
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| Pistorius, Pierre A.; Hindell, Mark A.; Tremblay, Yann; Rishworth, Gavin M.. |
| How animals respond to varying environmental conditions is fundamental to ecology and is a question that has gained impetus due to mounting evidence indicating negative effects of global change on biodiversity. Behavioural plasticity is one mechanism that enables individuals and species to deal with environmental changes, yet for many taxa information on behavioural parameters and their capacity to change are lacking or restricted to certain periods within the annual cycle. This is particularly true for seabirds where year-round behavioural information is intrinsically challenging to acquire due to their reliance on the marine environment where they are difficult to study. Using data from over 13,000 foraging trips throughout the annual cycle, acquired... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00626/73824/73686.pdf |
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| Assali, Camille; Bez, Nicolas; Tremblay, Yann. |
| Seabirds are known to concentrate on prey patches or at predators aggregations standing for potential feeding opportunities. They may search for prey using olfaction or by detecting visually feeding conspecifics and sub-surface predators, or even boats. Thus, they might form a foraging network. We hypothesized that conditionally to the existence of a foraging network, the visual detection ability of seabirds should have a bearing on their medium-scale distribution at sea. Using a fishing-boat radar to catch the instantaneous distribution of seabirds groups within 30 km around the vessel, we conducted a spatial clustering of the seabird-echoes. We found 7,657 clusters (i.e. aggregations of echoes), lasting less than 15 minutes and measuring 9.2 km in... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00625/73703/76150.pdf |
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| Thorne, Lesley H.; Hazen, Elliott L.; Bograd, Steven J.; Foley, David G.; Conners, Melinda G.; Kappes, Michelle A.; Kim, Hyemi M.; Costa, Daniel P.; Tremblay, Yann; Shaffer, Scott A.. |
| Background: Climate-driven environmental change in the North Pacific has been well documented, with marked effects on the habitat and foraging behavior of marine predators. However, the mechanistic linkages connecting climate-driven changes in behavior to predator populations are not well understood. We evaluated the effects of climate-driven environmental variability on the reproductive success and foraging behavior of Laysan and Black-footed albatrosses breeding in the Northwest Hawaiian Islands during both brooding and incubating periods. We assessed foraging trip metrics and reproductive success using data collected from 2002-2012 and 1981-2012, respectively, relative to variability in the location of the Transition Zone Chlorophyll Front (TZCF, an... |
| Tipo: Text |
Palavras-chave: Albatross; Movement; Reproductive success; Climate; Environmental variability. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00627/73882/73719.pdf |
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| Paredes, Rosana; Orben, Rachael A.; Roby, Daniel D.; Irons, David B.; Young, Rebecca; Renner, Heather; Tremblay, Yann; Will, Alexis; Harding, Ann M. A.; Kitaysky, Alexander S.. |
| Causes and consequences of differences in seabird foraging strategies between breeding colonies are not well understood. We tested whether body size of a pursuit-diving seabird, the thick-billed murre Uria lomvia, differs between breeding colonies and, if so, how size differences can be understood in the context of differences in foraging behavior, habitat use, and breeding performance. We measured adult murres over 3 seasons (2008 to 2010) at 2 of the Pribilof Islands, St. Paul and St. George, located on the continental shelf of the Bering Sea at different distances from the shelf break. Body mass and size were positively associated with deep diving and negatively associated with long flights, suggesting morphology influences foraging and commuting... |
| Tipo: Text |
Palavras-chave: Body size; Foraging; Diving; Marine habitats; Stress levels; Bering Sea; Murres; Seabirds. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00626/73837/73678.pdf |
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| Marques, Raquel; Darnaude, Audrey M.; Schiariti, Agustin; Tremblay, Yann; Molinero, Juan-carlos; Soriano, Solenn; Hatey, Elise; Colantoni, Sébastien; Bonnet, Delphine. |
| For many jellyfish, the magnitude and timing of medusae blooms are recognized to result from the benthic stage dynamics. However, information on the scyphistomae of jellyfish populations in the wild remains scarce. Here, bi-mensual underwater photoquadrat surveys were combined with scyphistomae sampling and observation to describe the annual (February 2017–January 2018) benthic stage dynamics and asexual reproduction strategy of Aurelia coerulea in the Thau lagoon (43°25′31.1″N; 03°42′0.9″E). Our results revealed unexpected seasonal patterns of variation: scyphistoma coverage peaked in the spring (11.6 ± 3.7% on 21st April) and was minimal in the summer and autumn (1.4 ± 1.3% on 10th October). The increase in scyphistoma coverage mainly resulted from an... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00497/60902/66960.pdf |
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| Barbraud, Christophe; Bertrand, Arnaud; Bouchon, Marilu; Chaigneau, Alexis; Delord, Karine; Demarcq, Herve; Gimenez, Olivier; Gutierrez Torero, Mariano; Gutierrez, Dimitri; Oliveros Ramos, Ricardo; Passuni, Giannina; Tremblay, Yann; Bertrand, Sophie. |
| In marine ecosystems top predator populations are shaped by environmental factors affecting their prey abundance. Coupling top predators' population studies with independent records of prey abundance suggests that prey fluctuations affect fecundity parameters and abundance of their predators. However, prey may be abundant but inaccessible to their predators and a major challenge is to determine the relative importance of prey accessibility in shaping seabird populations. In addition, disentangling the effects of prey abundance and accessibility from the effects of prey removal by fisheries, while accounting for density dependence, remains challenging for marine top predators. Here, we investigate how climate, population density, and the accessibility and... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00450/56117/57647.pdf |
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