Telemetry methods and remote sensing now make it possible to record the spatial usage of wide-ranging marine animals and the biophysical characteristics of their pelagic habitats. Furthermore, recent statistical advances mean that such data can be used to test ecological hypotheses and estimate species' distributions. Black-browed Albatrosses Thalassarche melanophrys are highly mobile marine predators with a circumpolar breeding and foraging distribution in the Southern Hemisphere. Although they remain relatively abundant, increased fisheries bycatch has led to their listing as endangered by conservation bodies. We satellite-tracked 163 breeding Black-browed Albatrosses and eight closely related Campbell Albatrosses T. impavida from nine colonies. We then quantified habitat usage, and modeled population-level spatial distribution at spatiotemporal scales .50 km and 1 month, as a function of habitat accessibility, habitat preference, and intraspecific competition, using mixed-effects generalized additive models (GAMM). During incubation, birds foraged over a wider area than in the post-brood chick-rearing period, when they are more time constrained. Throughout breeding, the order of habitat preference of Black-browed Albatrosses was for neritic (0-500 m), shelf-break and upper shelf-slope (500-1000 m), and then oceanic (.1000 m) waters. Black-browed Albatrosses also preferred areas with steeper (.38) bathymetric relief and, in addition, during incubation, warmer sea surface temperatures (peak preference ;168C). Although this suggests specialization in neritic habitats, incubation-stage Blackbrowed Albatrosses from South Georgia also foraged extensively in oceanic waters, preferring areas with high eddy kinetic energy (.250 cm 2 /s 2 ), especially the Brazil-Malvinas Confluence, a region of intense mesoscale turbulence. During chick-rearing, this species had a more southerly distribution, and following the seasonal retreat of sea ice, birds from some populations utilized neritic polar waters. Campbell Albatrosses showed similar bathymetric preferences but also preferred positive sea level anomalies. Black-browed Albatross foraging areas were partially spatially segregated with respect to colony and region, with birds preferring locations distant from neighboring colonies, presumably in order to reduce competition between parapatric conspecifics. At the global scale, the greatest concentrations of breeding Black-browed Albatrosses are in southern South American neritic, shelf-break, and shelf-slope waters. These regions also hold large fisheries and should therefore be a priority for introduction of bycatch mitigation measures.

International audienceSatellite telemetry data are a key source of animal distribution information for marine ecosystem management and conservation activities. We used two decades of telemetry data from the East Antarctic sector of the Southern Ocean. Habitat utilization models for the spring/summer period were developed for six highly abundant, wide-ranging meso- and top-predator species: Adélie Pygoscelisadeliae and emperor Aptenodytes forsteri penguins, light-mantled albatross Phoebetria palpebrata , Antarctic fur seals Arctocephalus gazella , southern elephant seals Mirounga leonina , and Weddell seals Leptony-chotes weddellii . The regional predictions from these models were combined to identify areas utilized by multiple species, and therefore likely to be of particular ecological significance. These areas were distributed across the longitudinal breadth of the East Antarctic sector, and were characterized by proximity to breeding colonies, both on the Antarctic continent and on subantarctic islands to the north, and by sea-ice dynamics, particularly locations of winter polynyas. These areas of important habitat were also congruent with many of the areas reported to be showing the strongest regional trends in sea ice seasonality. Th e results emphasize the importance of on-shore and sea-ice processes to Antarctic marine ecosystems. Our study provides ocean-basin-scale predictions of predator habitat utilization, an assessment of contemporary habitat use against which future changes can be assessed, and is of direct relevance to current conservation planning and spatial management efforts

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Pilot whales (Globicephala spp.) provide an interesting example of recently diverged oceanic species with a complex evolutionary history. The two species have wide but largely non-overlapping ranges. Globicephala melas (longfinned pilot whale; LFPW) has an antitropical distribution and is found in the cold-temperate waters of the North Atlantic and Southern Hemisphere, whereas Globicephala macrorhynchus (short-finned pilot whale; SFPW) has a circumglobal distribution and is found mainly in the tropics and subtropics. To investigate pilot whale evolution and biogeography, we analysed worldwide population structure using mitochondrial DNA (mtDNA) control region sequences (up to 620 bp) from a variety of sources (LFPW = 643; SFPW = 150), including strandings in New Zealand and Tasmania, and whale-meat products purchased on the markets of Japan and Korea. Phylogenetic reconstructions failed to support a reciprocal monophyly of the two species, despite six diagnostic substitutions, possibly because of incomplete lineage sorting or inadequate phylogenetic information. Both species had low haplotype and nucleotide diversity compared to other abundant widespread cetaceans (LFPW, p = 0.35%; SFPW, p = 0.87%) but showed strong mtDNA differentiation between oceanic basins. Strong levels of structuring were also found at the regional level. In LFPW, phylogeographic patterns were suggestive either of a recent demographic expansion or selective sweep acting on the mtDNA. For SFPW, the waters around Japan appear to represent a centre of diversity, with two genetically-distinct forms, as well as a third population of unknown origin. The presence of multiple unique haplotypes among SFPW from South Japan, together with previously documented morphological and ecological differences, suggests that the southern form represents a distinct subspecies and/or evolutionary significant unit.