Ecological Studies in the Antarctic Sea Ice Zone pp 148-156 | Cite as
Foraging behaviour of Weddell seals, and its ecological implications
Abstract
Time-depth recorder data of eight adult Weddell seals (Leptonychotes weddellii) provided simultaneous dive records over 8 days in the Drescher Inlet, eastern Weddell Sea coast, in February 1998. The seals primarily foraged within two depth layers, these being from the sea surface to 160 m where temperature and salinity varied considerably, and near the bottom from 340 to 450 m where temperature was lowest and salinity highest. While both pelagic and benthic diving occurred during daylight, the seals foraged almost exclusively in the upper water column at night. Trawling during daytime confirmed that Pleuragramma antarcticum were by far the most abundant fish both in the pelagial and close to the bottom. Pelagic night hauls at 110–170 m depth showed highly variable biomass of P.antarcticum. The temporal changes in the local abundance of P. antarcticum. particularly in the pelagial, may explain the trends in the seals’ pelagic and benthic foraging activities. This study describes the jaw movements of a hunting seal, which are presumably indicative of feeding events. Trophic links from the Weddell seal to fish, zooplankton and krill, Euphausia superba, are discussed.
Keywords
Antarctic Krill Dive Depth Weddell Seal Pelagic Trawl Crabeater SealPreview
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References
- Bengtson JL, Stewart BS (1992) Diving and haulout behavior of crabeater seals in the Weddell Sea, Antarctica. Polar Biol 12: 635 – 644CrossRefGoogle Scholar
- Bengtson JL, Stewart BS (1997) Diving patterns of a Ross seal near the eastern coast of the Antarctic Peninsula. Polar Biol 18: 214 – 218CrossRefGoogle Scholar
- Bornemann H, Mohr E, Plotz J, Krause G (1998) The tide as zeitgeber for Weddell seals. Polar Biol 20: 396 – 403CrossRefGoogle Scholar
- Burns JM, Schreer JF, Castellini MA (1997) Physiological effects on dive patterns and foraging strategies in yearling Weddell seals (Leptonychotes weddellii). Can J Zool 75: 1796 – 1810CrossRefGoogle Scholar
- Burns JM, Trumble S, Castellini M, Testa W (1998) The diet of Weddell seals in McMurdo Sound as determined from scat collections and stable isotope analysis. Polar Biol 19: 272 – 282CrossRefGoogle Scholar
- Castellini M, Davis R, Davis M, Horning M (1984) Antarctic marine life under the McMurdo ice shelf at White Island: a link between nutrient influx and seal population. Polar Biol 23: 229 – 231CrossRefGoogle Scholar
- Castellini M, Davis R, Kooyman G (1991) Annual cycles of diving behavior and ecology of the Weddell seal. Bull Scripps Inst Oceanogr 28: 1 – 54Google Scholar
- DeWitt HH (1970) The character of the midwater fish fauna of the Ross Sea, Antarctica. In: Holdgate MW (ed) Antarctic ecology, vol 1. Academic Press, London, pp 305 – 314Google Scholar
- Dieckmann G, Thomas D (1999) Organic matter production within, and export from Antarctic sea ice platelet layer. In: Arntz W, Gutt J (eds) Expedition Antarktis XV/3 (EAZIS II) of RV Polarstern 1998. Rep Polar Res 301: 118 – 323Google Scholar
- Graffe D, Niederjasper F (1997) Meeresbodenkartierung mit dem Hydrosweep-System. In: Jokat W, Oerter H (eds) Expedition Antarktis XII of RV Polarstern 1995. Rep Polar Res: 219: 37 – 44Google Scholar
- Hubold G (1985) Stomach contents of the Antarctic silver fish Pleuragramma antarcticumfrom the southern and eastern Weddell Sea (Antarctica). Polar Biol 5: 43 – 8CrossRefGoogle Scholar
- Hubold G, Hagen W (1997) Seasonality of feeding and lipid content in juvenile Pleuragramma antarcticumfrom the southern Weddell Sea. In: Battaglia B, Valencia J, Walton D (eds) Antarctic communities: species, structure and survival. University Press, Cambridge, pp 277 – 283Google Scholar
- Klages NTW, Cockcroft VG (1990) Feeding behaviour of a captive crabeater seal. Polar Biol 10: 403 – 2104Google Scholar
- Kooyman GL (1967) An analysis of some behavioral and physiological characteristics related to diving in the Weddell seal. In: Llano GA, Schmitt WL (eds) Antarctic Research Series (Biology of Antarctic Seas III). Am Geophys Union 11: 227 – 261Google Scholar
- Marschall HP (1988) The overwintering strategy of Antarctic krill under the pack-ice of the Weddell Sea. Polar Biol 9: 129 – 135CrossRefGoogle Scholar
- Olaso I (1999) The pelagic fish food web. In: Arntz W, Gutt J (eds) Expedition Antarktis XV/3 (EAZIS II) of RV Polarstern 1998. Rep Polar Res 301: 110 – 118Google Scholar
- Plotz J (1986) Summer diet of Weddell seals (Leptonychotes weddellii) in the eastern and southern Weddell Sea, Antarctica. Polar Biol 6: 97 – 102CrossRefGoogle Scholar
- Plotz J, Bornemann H, Gleitz M, Giinther S (1997) Biologische Untersuchungen im Drescher Inlet. In: Jokat W, Oerter H (eds) Expedition Antarktis-XII/3 of RV Polarstern 1995. Rep Polar Res 219: 61 – 66Google Scholar
- Rembizewski JM, Krzeptowski M, Linkowski TB (1978) Fishes as by-catch in fisheries of krill Euphausia superba. Pol Arch Hy-drobiol 25: 677 – 695Google Scholar
- Schenke HW, Diijkstra S, Niederjasper F, Schone T (1998) The new bathymetric charts of the Weddell Sea: AWI BCWS. Am Geophys Union, Antarct Res Ser 75: 371 – 380CrossRefGoogle Scholar
- Schreer JF, Testa JW (1996) Classification of Weddell seal diving behavior. Mar Mammal Sci 12: 227 – 250CrossRefGoogle Scholar
- Stretch JJ, Hamner PP, Hamner WM, Michel WC, Cook J, Sullivan CW (1988) Foraging behavior of Antarctic krill Euphausia superbaon sea ice microalgae. Mar Ecol Prog Ser 44: 131 – 139CrossRefGoogle Scholar
- Testa JW (1994) Over-winter movements and diving behavior of female Weddell seals (Leptonychotes weddellii) in the southwestern Ross Sea, Antarctica. Can J Zool 72: 1700 – 1710CrossRefGoogle Scholar
- Wöhrmann A, Hagen W, Kunzmann A (1997) Adaptations of the Antarctic silverfish Pleuragramma antarcticum(Pisces:Noto- theniidae) to pelagic life in high-Antarctic waters. Mar Ecol Prog Ser 151: 205 – 218CrossRefGoogle Scholar