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Registros recuperados: 56 | |
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Campos, L. F. A. S.; Andrade, A. B.; Bertrand, Sophie; Efe, M. A.. |
We used miniaturized GPS loggers and site observations to access foraging patterns and nest behaviour of the White-tailed Tropicbird Phaethon lepturus (WTTB), an endangered species at its South Atlantic breeding colony. Dual foraging pattern was observed with alternation between long and short foraging trips. Birds responsible for nest attendance engaged in short foraging trips with mean distance from colony of 25 +/- 17 km, total distance covered of 79 +/- 65 km and mean duration of 4.02 +/- 5.28 hours. Birds flew by dawn and returned before dusk while partners were at sea for long foraging trips that ranged from four to 11 days, with mean maximum distance from colony of 105 +/- 47.48 km. Chicks were usually left alone for hours and chick predation by... |
Tipo: Text |
Palavras-chave: Tropicbird; GPS; Dual foraging; Behavior. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00626/73778/74931.pdf |
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Weimerskirch, Henri; Le Corre, Matthieu; Jaquemet, Sébastien; Marsac, Francis. |
The foraging behaviour of animals depends on the distribution, abundance and predictability of their food resources. In the marine environment, top predators such as seabirds are known to concentrate their foraging effort in specific oceanic features where productivity is elevated or prey concentrated. When marine productivity is low and prey distribution unpredictable, such as in tropical waters, selection should favour the evolution of flexible foraging strategies. By using GPS, Argos transmitters and activity recorders, we studied the foraging strategy of red-footed boobies (RFBs) Sula sula breeding on Europa Island in the Mozambique Channel, to examine the way a central place forager searches for prey in tropical waters. RFBs only foraged during the... |
Tipo: Text |
Palavras-chave: Sula sula; GPS; Satellite tracking; Mozambique Channel; Chlorophyll concentration; Sea-level height anomalies. |
Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00209/32068/30526.pdf |
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Walker, Emily; Rivoirard, Jacques; Gaspar, Philippe; Bez, Nicolas. |
In the open ocean, movements of migratory fish populations are typically surveyed using tagging methods that are subject to low sample sizes for archive tags, except for a few notable examples, and poor temporal resolution for conventional tags. Alternatively, one can infer patterns of movement of migratory fish by tracking movements of their predators, i.e., fishing vessels, whose navigational systems (e.g., GPS) provide accurate and frequent VMS (vessel monitoring system) records of movement in pursuit of prey. In this paper, we develop a state-space model that infers the foraging activities of fishing vessels from their tracks. Second, we link foraging activities to probabilities of tuna presence. Finally, using multivariate geostatistical interpolation... |
Tipo: Text |
Palavras-chave: GPS; Multivariate geostatistics; Presence index; Spatiotemporal distribution; Trajectometry; Tropical tuna; Vessel monitoring system (VMS). |
Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00610/72249/71048.pdf |
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Registros recuperados: 56 | |
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