The diet of the Weddell seal Leptonychotes weddelli at Harmony Point, South Shetland Islands

Casaux, Ricardo; Baroni, A.; Carlini, Alejandro R

doi:10.1007/s003000050202

Cited by 40 publications

(28 citation statements)

References 10 publications

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“…However, the resulting estimate of 250 g was large compared to observations from Weddell seal regurgitates (S. Lake unpubl. data), and also the masses estimated by Casaux et al (1997) for octopus in the Weddell seal diet and the relatively small mantle lengths described by Allcock et al (2001). Considering this, we made a general estimate for octopus body mass at 100 g.…”

Section: Methodssupporting

confidence: 53%

“…In the Weddell seal diet, abundance of cephalopods was markedly higher at Mawson (82% mass, Table 1) than at the Vestfold Hills (2%), Larsemann Hills (2%), and Commonwealth Bay (10%), and at other sites around the Antarctica continent (4 to 21% mass, Plötz 1996, Castellini et al 1992, Burns et al 1998). The only location, apart from Mawson, where Weddell seal diet had a large component of cephalopods was the South Shetland Islands in the Scotia Arc, sub-Antarctic (91% mass, Casaux et al 1997). As fish predators (Roper et al 1985, Daly & Rodhouse 1994, cephalopods represent another level of complexity in the food web.…”

Section: Mawsonmentioning

confidence: 99%

“…At the South Shetland Islands, they took myctophids instead of Pleuragramma antarcticum, and took benthic fish typical of the sub-Antarctic islands instead of Trematomus spp. (Casaux et al 1997). Such regional variation in diet demonstrates the flexibility of Weddell seal foraging.…”

Section: Regional Comparisonsmentioning

confidence: 99%

“…Pelagic fish are predominant in the diet in McMurdo Sound (Testa et al 1985, Burns et al 1998. Cephalopods are the main prey type at both South Shetland Islands and Mawson (Lipinski & Woyciechowski 1981, Clarke & McLeod 1982, Green & Burton 1987, Casaux et al 1997. Both benthic and pelagic fish are consumed over the continental slope in the Weddell Sea (Plötz 1986, Plötz et al 1991.…”

Section: Introductionmentioning

confidence: 99%

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Regional, temporal and fine-scale spatial variation in Weddell seal diet at four coastal locations in east Antarctica

Lake

Burton²,

Hoff³

2003

Mar. Ecol. Prog. Ser.

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This description of 905 scats from 4 locations in east Antarctica almost doubles the observations of Weddell seal diet reported to date. Regional, temporal and fine-scale spatial variation in diet was evaluated using both randomisation and parametric statistics. Even within the Vestfold Hills (68°33' S, 78°15' E) there were several different ecotypes. In the southern fjords the diet was benthic fish and prawns, whereas in the northern area the diet was dominated numerically by Pleuragramma antarcticum -a species of pelagic schooling fish. Along the Mawson coast (68°00' S, 63°00' E) the diet was spatially homogeneous but varied over time. Squid Psychroteuthis glacialis was an important prey type for a short time in spring, and octopus was also abundant in the Mawson diet. As higher order predators, cephalopods represent another layer of complexity in the food web at Mawson. Both Vestfold Hills and Mawson seemed to be good foraging areas compared with Commonwealth Bay (67°00' S, 142°30' E) and Larsemann Hills (69°24' S, 76°13' E), where seals appeared to have eaten less during the summer haul-out period. This investigation described inshore diets using scats from coastal haul-out sites; it also showed that small crustaceae (mysids) were an important prey type, thus revealing the capacity for Weddell seals to join the krill-feeding communities north of the continental shelf. The variety in diet composition demonstrated both flexibility in the Weddell seals' foraging response and the range of different prey species available to Weddell seals over the Antarctic continental shelf and slope. In all but the most southerly area reported to date (McMurdo Sound), the seals take multiple prey species, which may minimise the coupling between Weddell seal population dynamics and the dynamics of their prey.

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Section: Methodssupporting

confidence: 53%

Section: Mawsonmentioning

confidence: 99%

Section: Regional Comparisonsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Regional, temporal and fine-scale spatial variation in Weddell seal diet at four coastal locations in east Antarctica

Lake

Burton²,

Hoff³

2003

Mar. Ecol. Prog. Ser.

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“…However, diet data for marine piscivores is limited outside of McMurdo Sound and myctophids are mesopelagic in waters of the continental slope and beyond (Eastman and Hubold 1999). Certainly, myctophid species are an important diet component for Weddell seals inhabiting sub-Antarctic islands (Casaux et al 1997(Casaux et al , 2006 as well as for southern elephant seals , Antarctic fur seals (Green et al 1991;Lea et al 2002a;Staniland et al 2010), penguins (Hindell 1989;Hull 1999) and seabirds (Connan et al 2008).…”

Section: Discussionmentioning

confidence: 99%

Proximate composition and energy density of nototheniid and myctophid fish in McMurdo Sound and the Ross Sea, Antarctica

et al. 2011

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Nototheniid and myctophid Wsh are primary prey for marine piscivores, yet little is known about their nutritional value. In this study, we characterized the proximate composition [PC: water, fat (neutral lipids), crude protein (CP) and ash] and energy density (ED; kJ g ¡1 ) of Wfteen Wsh species from McMurdo Sound and the Ross Sea, Antarctica. We assayed the entire Wsh for all species except for the large Antarctic toothWsh, Dissostichus mawsoni (muscle tissue only). On a wet mass basis (WM), Wsh were variable in composition: moisture content ranged from 64.9 to 87.3% WM, fat from 0.5 to 17.4% WM, CP from 7.7 to 16.7% WM, ash from 11.2 to 21.0% FFDM (fat-free dry mass), and ED from 2.9 to 10.3 kJ g ¡1 . Myctophids and pelagic nototheniids such as Pleuragramma antarcticum and D. mawsoni were high in fat content (7-17% WM), while a bathylagid and benthic nototheniids including most Trematomus spp. and Lepidonotothen squamifrons were low in fat (0.5-4% WM). The epibenthic Trematomus species (T. eulepidotus and T. lepidorhinus) were intermediate. Energy density tracked fat content, with highest values in myctophids and pelagic nototheniids. The variation in nutrient and energy density conWrms that prey composition must be taken into account when modelling energy and nutrient Xuxes within the Antarctic ecosystem. Further analyses of prey collected over a number of diVerent locations and seasons are needed in order to determine how the nutritional value of certain species might aVect annual or decadal variation in reproductive success or population size of top predators.

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Geographical variation in the diet of the Antarctic fur seal Arctocephalus gazella

Casaux

Baroni²,

Arrighetti

et al. 2003

Polar Biology

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The diet of the Weddell seal Leptonychotes weddelli at Harmony Point, South Shetland Islands

Cited by 40 publications

References 10 publications

Regional, temporal and fine-scale spatial variation in Weddell seal diet at four coastal locations in east Antarctica

Regional, temporal and fine-scale spatial variation in Weddell seal diet at four coastal locations in east Antarctica

Proximate composition and energy density of nototheniid and myctophid fish in McMurdo Sound and the Ross Sea, Antarctica

Geographical variation in the diet of the Antarctic fur seal Arctocephalus gazella

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