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Gabarrou J.F., Duchamp C., Williams J. & Geraert P.A. (1997). A role for thyroid hormones in the regulation of diet-induced thermogenesis in birds. Br. J. Nutr., 78, 963–973.
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Koubbi, P.; Duhamel, G.; Hecq, J.-H.; Beans, C.; Loots, C.; Pruvost, P.; Tavernier, E.; Vacchi, M.; Vallet, C. (2009). Ichthyoplankton in the neritic and coastal zone of Antarctica and Subantarctic islands: A review. Revisiting the Role of Zooplankton in Pelagic Ecosystems, 78(4), 547–556.
Abstract: Since the article published by Loeb et al. [Loeb, V.J., Kellermann, A., Koubbi, P., North, A.W., White, M., 1993. Antarctic larval fish assemblages: a review. Bull. Mar. Sci. 53(2), 416-449.] about Antarctic ichthyoplankton, many surveys were carried out in different sectors of the Southern Ocean focusing on different aspects of the ecology of fish larvae. Some of these researches were conducted in the Subantarctic Kerguelen Islands and others on the continental shelf off Terre Adlie and Georges V land. Oceanographic and geographic features influence fish larvae ecology such as island mass effects, gyres, canyons. Antarctic fishes show also temporal segregation of spawning which induces temporal succession of early stage larvae. This avoids competition and probably the predation on early stages for species having few recruits. In that case, we have to understand how these larvae can deal with the match-mismatch with their preys and how they find sufficient food to survive. But our knowledge on Antarctic fish larvae is still insufficient as we do not know larvae for quite a lot of species and because of the difficulty to sample during winter.
Keywords: Fish larvae; Southern Ocean; Match-mismatch; Distribution; Life cycle
Programme: 1142
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Roquet, F.; Park, Y.-H.; Guinet, C.; Bailleul, Frdric; Charrassin, Jean-Benot. (2009). Observations of the Fawn Trough Current over the Kerguelen Plateau from instrumented elephant seals. Special Issue on Observational Studies of Oceanic Fronts, 78(3), 377–393.
Abstract: Due to its great meridional extent and relatively shallow depths, the Kerguelen Plateau constitutes a major barrier to the eastward flowing Antarctic Circumpolar Current in the Indian sector of the Southern Ocean. While most of the Antarctic Circumpolar Current transport is deflected north of the Kerguelen Islands, the remainder (~50Sv, 1Sv=106m3 s-1) must pass south of the islands, most probably through the Fawn and Princess Elizabeth Troughs. However, the paucity of finely resolved quasi-synoptic hydrographic data in this remote and infrequently sampled area has limited the progress in our knowledge of the regional circulation. Since 2004, a new approach using elephant seals from the Kerguelen Islands as autonomous oceanographic profilers has provided new information on the hydrography over the Kerguelen Plateau, covering the entire Antarctic Zone between the Polar Front and Antarctica, with a mean along-track resolution of about 25km. These finely resolved bio-logged data revealed details of a strong northeastward current found across the Fawn Trough (sill depth: 2600m; 56S, 78E). This so-called Fawn Trough Current transports cold Antarctic waters found mostly south of the Elan Bank, between the Ice Limit (58S) and the Antarctic Divergence (64S) in the eastern Enderby Basin, toward the Australian-Antarctic Basin. Our analysis also demonstrates that the Deep Western Boundary Current, which carries cold Antarctic water along the eastern flank of the southern Kerguelen Plateau collides with Fawn Trough Current at the outlet of the Fawn Trough sill. In other words, the Fawn Trough constitutes a veritable bottleneck, channelling the quasi-totality of the Antarctic Circumpolar flow found south of the Polar Front. Thanks to the unprecedented fine resolution of seal-borne data, a branch of flow centered at the Winter Water isotherm of 1C is also revealed along the northern escarpment of the Elan Bank, and then along the southern edge of Heard Island. Further analysis of different supplementary data reveals a complex circulation pattern in the entire Enderby Basin, with several distinctive branches of flow being strongly controlled by prominent topographic features such as the Southwest Indian Ridge, Conrad Rise, Elan Bank, and Kerguelen Plateau. This newly emerged frontal structure refines considerably previous large-scale circulation schematics of the area.
Keywords: Fawn Trough Current; Kerguelen Plateau [46-62S, 65-85E ]; Ocean circulation; Oceanic fronts; Southern Ocean; Bio-logging; Elephant seals
Programme: 109
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Weimerskirch, H.; Cherel, Y.; Cuenot-Chaillet, F.; Ridoux, V. (1997). Alternative foraging strategies and resource allocation by male and female wandering albatrosses. Ecology, 78(7), 2051–2063.
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Beaulieu M., Raclot T., Dervaux A., Le Maho Y., Ropert-Coudert Y. & Ancel A. (2009). Can a handicapped parent rely on its partner? An experimental study within Adélie penguin pairs. ANIMAL BEHAVIOUR, 78, 313–320.
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Bost, C.A.; Cott, C.; Bailleul, F.; Cherel, Y.; Charrassin, J.B.; Guinet, C.; Ainley, D.G.; Weimerskirch, H. (2009). The importance of oceanographic fronts to marine birds and mammals of the southern oceans. Special Issue on Observational Studies of Oceanic Fronts, 78(3), 363–376.
Abstract: During the last 30years, at-sea studies of seabirds and marine mammals in the oceans south of the Subtropical Front have described an association with major frontal areas. More recently, the advancement in microtechnology has allowed the tracking of individuals and investigations into how these marine predators actually use the frontal zones. In this review, we examine 1) the relative importance to apex predators of the different frontal zones in terms of spatial distribution and carbon flux; 2) the processes that determine their preferential use; and 3) how the mesoscale dynamics of frontal structures drive at-sea foraging strategies of these predators. We review published results from southern waters and place them in a broader context with respect to what has been learned about the importance of fronts in oceans farther north.
Some fronts constitute important boundaries for seabird communities in southern waters. At a mesoscale the maximum values of seabird diversity and abundance correspond to the location of the main fronts. At-sea surveys show a strong curvilinear correlation between seabird abundance and sea surface temperatures. High mean species richness and diversity for whales and seabirds are consistently associated with the southern water mass boundary of the Antarctic Circumpolar Current, the Subtropical Front and the Subantarctic Front; in the case of the Polar Front mean seabird densities are more variable. At small-scales, variation in seabird occurrence has been directly related to the processes at fronts in a limited number of cases. A significant positive relation was found between some plankton feeding species and frontal temperature gradient-phytoplankton variables.
Telemetric studies have revealed that several apex predators (penguins, albatrosses, seals) perform long, directed foraging trips either to the Subtropical front or Polar Front, depending on locality. Seabirds with low flight costs, such as albatrosses, are able to reach fronts at long distances from colonies, showing variable foraging strategies as a function of the distances involved. Diving birds such as King penguins, that travel at a higher cost and lower speed, rely on the predictable spatial distribution of mesopelagic fish found close to the Polar Front. They may use the currents associated with eddies as oceanographic cues in the active search for frontal zones. Once in these areas they dive preferentially in and below the depth of the thermocline where catches per unit effort are high. Elephant seals concentrate foraging activity principally inside or at the boundary of cyclonic eddies. These mesoscale features appear to offer exceptional productivity favourable for foraging by various diving top predators.
The connection between biophysical parameters at fronts and predators is likely to be made through biological enhancement. Top predators appear to forage at locations where prey are advected by physical processes and others where prey are produced locally. Long-term research on at-sea distributions and demographic parameters of top predators are essential to assess the consequences of potential shift in front distributions in relation to global warming. Such environmental changes would add to the impact of fish extraction by the industrial fisheries on the southern food webs.
Keywords: Seabird; Sea mammals; Fronts; Foraging strategies; Bio-logging
Programme: 109; 394
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Bailleul F., Pinaud D., Hindell M., Charrassin J.-B. & Guinet C. (2008). Assessment of scale-dependent foraging behaviour in southern elephant seals incorporating the vertical dimension : a development of the First Passage Time method. Journal of animal ecology, 77, 948–957.
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Bailleul F., Pinaud D., Charrassin J.-B., Guinet, C. (2008). Scale-dependent foraging behaviour of the Southern elephant seal (Mirounga Leonina) : an approach in depth using First Passage Time derived. JOURNAL OF ANIMAL ECOLOGY, 77, 948–957.
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Guinet C., Roux J.P., Bonnet M. & Mison V. (1998). Effects of size, Weight and Body condition on reproduction of female Cape fur seal (Arctocephalus pusillus) in Namibia. Can. J. Zool., 76, 1418–1424.
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Gendner J.P., Gauthier-Clerc M., Le Bohec C., Descamps S. & Le Maho Y. (2004). A new application for transponders in studying of penguins. J Field Ornithol, 76(2), 138–142.
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