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Viviant Morgane, Jeanniard?du?Dot Tiphaine, Monestiez Pascal, Authier Matthieu, Guinet Christophe, Costa Daniel. (2016). Bottom time does not always predict prey encounter rate in Antarctic fur seals (Vol. 30).
Keywords: aerobic diving limit Antarctic fur seals diving behaviour foraging depth foraging strategies
Programme: 109
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. (2016). Flight paths of seabirds soaring over the ocean surface enable measurement of fine-scale wind speed and direction (Vol. 113).
Abstract: Ocean surface winds are an essential factor in understanding the physical interactions between the atmosphere and the ocean. Surface winds measured by satellite scatterometers and buoys cover most of the global ocean; however, there are still spatial and temporal gaps and finer-scale variations of wind that may be overlooked, particularly in coastal areas. Here, we show that flight paths of soaring seabirds can be used to estimate fine-scale (every 5 min, ?5 km) ocean surface winds. Fine-scale global positioning system (GPS) positional data revealed that soaring seabirds flew tortuously and ground speed fluctuated presumably due to tail winds and head winds. Taking advantage of the ground speed difference in relation to flight direction, we reliably estimated wind speed and direction experienced by the birds. These bird-based wind velocities were significantly correlated with wind velocities estimated by satellite-borne scatterometers. Furthermore, extensive travel distances and flight duration of the seabirds enabled a wide range of high-resolution wind observations, especially in coastal areas. Our study suggests that seabirds provide a platform from which to measure ocean surface winds, potentially complementing conventional wind measurements by covering spatial and temporal measurement gaps.
Keywords: biologging dynamic soaring GPS meteorology satellite scatterometer
Programme: 109
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Abadi Fitsum, Barbraud Christophe, Gimenez Olivier. (2017). Integrated population modeling reveals the impact of climate on the survival of juvenile emperor penguins (Vol. 23).
Keywords: Bayesian climate change emperor penguins integrated population model sea ice concentration southern annular mode survival
Programme: 109
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. (2017). From Antarctica to the subtropics: Contrasted geographical concentrations of selenium, mercury, and persistent organic pollutants in skua chicks (Catharacta spp.) (Vol. 228).
Keywords: Bioaccumulation Blood Chick HCB Southern Ocean Stable isotopes
Programme: 109
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. (2017). Measuring the Marine Soundscape of the Indian Ocean with Southern Elephant Seals Used as Acoustic Gliders of Opportunity (Vol. 34).
Abstract: The underwater ambient sound field contains quantifiable information about the physical and biological marine environment. The development of operational systems for monitoring in an autonomous way the underwater acoustic signal is necessary for many applications, such as meteorology and biodiversity protection. This paper develops a proof-of-concept study on performing marine soundscape analysis from acoustic passive recordings of free-ranging biologged southern elephant seals (SES). A multivariate multiple linear regression (MMLR) framework is used to predict the measured ambient noise, modeled as a multivariate acoustic response, from SES (depth, speed, and acceleration) and environmental (wind) variables. Results show that the acoustic contributions of SES variables affect mainly low-frequency sound pressure levels (SPLs), while frequency bands above 3 kHz are less corrupted by SES displacement and allow a good measure of the Indian Ocean soundscape. Also, preliminary results toward the development of a mobile embedded weather sensor are presented. In particular, wind speed estimation can be performed from the passive acoustic recordings with an accuracy of 2 m s?1, using a rather simple multiple linear model.
Programme: 109
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. (2017). Feeding ecology, isotopic niche, and ingestion of fishery-related items of the wandering albatross Diomedea exulans at Kerguelen and Crozet Islands (Vol. 565).
Abstract: Feeding ecology and isotopic niche of the wandering albatross Diomedea exulans were investigated in the poorly studied population on the Kerguelen Islands and compared to that on the Crozet Islands. Fish (48% by mass) and cephalopods (46%) were similarly important in chick food at Kerguelen, while cephalopods (87%) dominated the diet at Crozet. Fish prey included mainly deep-sea species, with the Patagonian toothfish Dissostichus eleginoides being the main item. Cephalopod beaks were identified, most of which were from adult oceanic squids. Albatrosses preyed upon the same taxa at both localities, but in different proportions. Histioteuthis atlantica (30% by number), Galiteuthis glacialis (13%), and Kondakovia longimana (10%) were the main squid prey at Kerguelen, while K. longimana (35%) and H. eltaninae (23%) dominated at Crozet. Chick feather ?15N values were higher in wandering albatrosses than in other oceanic seabirds of the 2 communities, indicating that the wandering albatross is an apex consumer together with the sperm whale and sleeper shark that have similar ?15N values. Satellite-tracked wandering albatrosses foraged in local subantarctic waters and farther north, with some Crozet birds overlapping with those from the Kerguelen population in western Kerguelen waters. Anthropogenic items (e.g. plastic fragments, hooks) were found in half the food samples. All fishery-related items were from the local toothfish fishery. The high number of hooks from Crozet indicated the presence of a fairly large number of illegal longliners in the area during the Austral winter 1998. A review of the feeding habits of Diomedea spp. highlights the need for more dietary investigations to achieve effective conservation and management of this endangered group of charismatic seabirds.
Keywords: Cephalopod Diet Hook Satellite tracking Seabird Southern Ocean Stable isotopes
Programme: 109
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Collet Julien, Patrick Samantha C., Weimerskirch Henri. (2017). Behavioral responses to encounter of fishing boats in wandering albatrosses (Vol. 7).
Abstract: Animals are attracted to human food subsidies worldwide. The behavioral response of individuals to these resources is rarely described in detail, beyond chances of encounters. Seabirds for instance scavenge in large numbers at fishing boats, triggering crucial conservation issues, but how the response to boats varies across encounters is poorly known. Here we examine the behavioral response of wandering albatrosses (Diomedea exulans), equipped with GPS tags, to longline fishing boats operating near their colony for which we had access to vessel monitoring system data. We distinguish between encounters (flying within 30 km of a boat) and attendance behavior (sitting on the sea within 3 km of a boat), and examine factors affecting each. In particular, we test hypotheses that the response to encountered boats should vary with sex and age in this long?lived dimorphic species. Among the 60% trips that encountered boats at least once, 80% of them contained attendance (but attendance followed only 60% of each single encounter). Birds were more attracted and remained attending longer when boats were hauling lines, despite the measures enforced by this fleet to limit food availability during operations. Sex and age of birds had low influence on the response to boats, except the year when fewer boats came fishing in the area, and younger birds were attending further from boats compared to older birds. Net mass gain of birds was similar across sex and not affected by time spent attending boats. Our results indicate albatrosses extensively attend this fishery, with no clear advantages, questioning impacts on foraging time budgets. Factors responsible for sex foraging segregation at larger scale seem not to operate at this fleet near the colony and are not consistent with predictions of optimal foraging theory on potential individual dominance asymmetries. This approach complements studies of large?scale overlap of animals with human subsidies.
Keywords: competition fisheries foraging decisions movement ecology seabirds vessel monitoring system
Programme: 109
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. (2017). Fathers matter: male body mass affects life-history traits in a size-dimorphic seabird (Vol. 284).
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Louise Day, Joffrey Jouma'a, Julien Bonnel, Christophe Guinet. (2017). Acoustic measurements of post-dive cardiac responses in southern elephant seals (Mirounga leonina) during surfacing at sea (Vol. 220).
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. (2017). Contrasting effects of climate and population density over time and life stages in a long?lived seabird (Vol. 31).
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