Colin Southwell, Louise Emmerson, Akinori Takahashi, Akiko Kato, Christophe Barbraud, Karine Delord, Henri Weimerskirch. (2017). Recent studies overestimate colonization and extinction events for Adelie Penguin breeding colonies (Vol. 134).
Abstract: Modeling metapopulation dynamics is potentially a useful and powerful tool for ecologists and conservation biologists. However, the key processes driving metapopulation dynamics are colonization and extinction events, which are notoriously difficult to study. A recent global assessment of Adelie Penguin (Pygoscelis adeliae) breeding populations reported multiple potential colonization and extinction events from occupancy observations using recent high-resolution satellite imagery and examination of historical occupancy literature, but emphasized that the events should be confirmed with direct observations. We evaluated these conclusions by developing a comprehensive database of direct observations of Adelie Penguin breeding site occupancy across East Antarctica. The database allowed 16 of 19 proposed colonization and extinction events in this region to be evaluated using direct observations that were concurrent in space and time (same breeding season) with observations from satellite imagery. We concluded that none of the 16 proposed colonization and extinction events had occurred. One true extinction event may have been correctly identified from satellite imagery, but a conclusive evaluation was not possible because the direct and satellite observations were not concurrent in time. The evaluation identified several sources of error in observations from satellite imagery, including errors of omission through failure to detect small colonies and errors of commission through misidentification of other biological and physical features as Adelie Penguin guano. The occupancy database corrected issues of poor precision and accuracy in locations of historical occupancy data. Our results improve understanding of key parameters for Adelie Penguin metapopulation dynamics and facilitate improved interpretation of satellite imagery in the future.
Programme: 109
|
. (2017). Important marine sectors for the top predator community around Kerguelen Archipelago (Vol. 40).
|
. (2017). (Vol. 98).
|
PICARD B. (2017). Les éléphants de mer auxiliaires d’étude à la description de l’océanographie physique et à l’écologie marine.
|
C. Barbraud, J. Vasseur, K. Delord. (2017). (Vol. 41).
|
. (2017). Acoustic distribution of discriminated micronektonic organisms from a bi-frequency processing: The case study of eastern Kerguelen oceanic waters (Vol. 156).
Keywords: Acoustics Euphausiid Kerguelen Myctophid Southern Ocean
Programme: 109
|
Caio V. Z. Cipro, Y. Cherel, P. Bocher, F. Caurant, P. Miramand, P. Bustamante. (2017). Trace elements in invertebrates and fish from Kerguelen waters, southern Indian Ocean (Vol. 41).
Abstract: Given the lack of background data on essential and non-essential trace elements in invertebrates and fish known to be the predominant prey of marine mammals and seabirds breeding at the Kerguelen Islands, this study intends to provide these results of great influence for predators in higher trophic levels. To this end, plankton organisms (9 species/4 phyla), mollusks (2 bivalves and 2 squid species) and fishes (8 benthic and 10 pelagic species) from Kerguelen waters were analysed for cadmium (Cd), copper (Cu), mercury (Hg) and zinc (Zn). Individual concentrations of non-essential elements (particularly Cd) showed larger variation in comparison with essential ones likely due to their homeostasis. Thus Cd ranged over 4 orders of magnitude; however, Hg ranged only 1, without significant correlation to trophic level. Instead, ecological parameters (benthic/mesopelagic habitat and feeding ecology) showed a more important influence on the results. Concerning seashore organisms, bivalves collected inside the Gulf of Morbihan had higher Cd concentrations compared to those from the Kerguelen shelf, suggesting a local source of Cd, such as runoff water from bird colonies. Comparison with the literature showed metal concentrations in invertebrates and fishes from Kerguelen Islands somewhat lower than those in the Antarctic area, with Hg prevailing in benthic species and Cd in pelagic ones. In contrast to Hg, Cd values of squids, jellyfish and the amphipod Themisto gaudichaudii were significantly higher than all other species. Finally, top predators foraging in this area that can be subject to potentially high Hg and Cd exposure through their diet at Kerguelen are reviewed.
Programme: 109
|
Julien Collet, Samantha C. Patrick, Henri Weimerskirch. (2017). A comparative analysis of the behavioral response to fishing boats in two albatross species (Vol. 28).
Abstract: Anthropogenic food resources have significantly modified the foraging behavior of many animal species. They enhance large multi-specific aggregations of individuals, with strong ecological consequences. It is challenging to predict how individuals or species can differ in their reaction to these resources. For instance, there are wide variations in seabird species abundance behind fishing boats, and individual variations in interaction rates. Whether this is reflecting variations in fine-scale encounter rates or rather variations in attraction strength is poorly quantified. Here we compare the response of Wandering (WA) and Black-browed (BBA) albatrosses to fishing boats operating in sub-Antarctic waters. We use GPS tracking data from both birds and boats (Vessel Monitoring System). Attraction distances were similar between the 2 species (up to 30 km). BBA foraged further from fishing grounds and encountered boats less frequently than WA, but once they encountered a boat BBA were more strongly attracted (80% vs. 60% chance) and had a higher level of active interaction, compared to WA. Furthermore, in the absence of boats, BBA were rarely observed foraging over the habitat where the fisheries mainly operate, in contrast with WA. We thus report qualitative and quantitative differences in the response of these 2 species to the same fishing fleet. WA, the larger, more dominant and more generalist species was unexpectedly less attracted to fishing vessels. Comparing our results with previously published studies, we suggest that energetic requirements of individuals may be a crucial predictor for assessing risks of interactions with anthropogenic food resources.
Programme: 109
|
Cox Sam L., Orgeret Florian, Gesta Mathieu, Rodde Charles, Heizer Isaac, Weimerskirch Henri, Guinet Christophe, O'Hara Robert B. (2017). Processing of acceleration and dive data on?board satellite relay tags to investigate diving and foraging behaviour in free?ranging marine predators (Vol. 9).
|
Grissac Sophie, Bartumeus Frederic, Cox Sam L., Weimerskirch Henri. (2017). Early?life foraging: Behavioral responses of newly fledged albatrosses to environmental conditions (Vol. 7).
|