Fish in the diet of Antarctic fur seals (Arctocephalus gazella) at South Georgia during winter and spring

1996 ◽  
Vol 8 (2) ◽  
pp. 155-160 ◽  
Author(s):  
A.W. North

The occurrence of fish in the diet of the Antarctic fur seal (Arctocephalus gazella) at Bird Island, South Georgia was investigated by analysis of fish otoliths in scats (faeces) collected during late May to early November 1983. Of the 55 scats examined, 49 contained fish remains, and 45 contained fish otoliths. Ten fish species were represented by 415 otoliths, and 33 otoliths were too digested to be identified unequivocally. Fish size was estimated from otolith size based on published allometric equations. Four coastal notothenioid fishes dominated the fish component of the diet: Champsocephalus gunnari and Gobionotothen gibberifrons each comprised about 40% of the total fish mass; Chaenocephalus aceratus was ranked third by mass and the smaller Lepidonotothen larseni occurred in one quarter of the scats but was of lower importance in terms of mass. The length-frequency distribution of C. gunnari landed by the commercial fishery in October 1982 to June 1983 is similar to that which comprised the bulk of the diet in the present study. Compared with recent studies on the fish component of the diet in the literature, the dominance of C. gunnari is generally similar, however, there was a greater proportion of G. gibberifrons during the 1983 winter and spring than reported for recent winters.

Polar Record ◽  
1991 ◽  
Vol 27 (162) ◽  
pp. 245-248 ◽  
Author(s):  
K. Townrow ◽  
P. D. Shaughnessy

AbstractFur seals were exterminated from Macquarie Island about 20 years after discovery of the island in 1810. Their specific identity is unknown. Few fur seals were reported at the island until it was occupied by the Australian National Antarctic Research Expeditions in 1948. Fur seal numbers are now increasing. An archaeological excavation at a sealers' quarters at Sandy Bay in 1988 revealed the fragmented skull of a young Antarctic fur sealArctocephalus gazella1.1 m below the surface in a layer dated in the 1870s and 1880s. This period coincides with the recovery of fur seal populations in the South Atlantic Ocean following earlier harvesting. Elsewhere it has been argued that the Antarctic fur seal is unlikely to have been the original fur seal at Macquarie Island because few individuals of that species are ashore in winter, which is the season when the island was discovered and fur-seal harvesting began. It is concluded that the Sandy Bay skull is from a vagrant animal.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248071
Author(s):  
Connor C. G. Bamford ◽  
Victoria Warwick-Evans ◽  
Iain J. Staniland ◽  
Jennifer A. Jackson ◽  
Philip N. Trathan

The diet of Antarctic fur seals (Arctocephalus gazella) at South Georgia is dominated by Antarctic krill (Euphausia superba). During the breeding season, foraging trips by lactating female fur seals are constrained by their need to return to land to provision their pups. Post-breeding, seals disperse in order to feed and recover condition; estimates indicate c.70% of females remain near to South Georgia, whilst others head west towards the Patagonian Shelf or south to the ice-edge. The krill fishery at South Georgia operates only during the winter, providing the potential for fur seal: fishery interaction during these months. Here we use available winter (May to September) tracking data from Platform Terminal Transmitter (PTT) tags deployed on female fur seals at Bird Island, South Georgia. We develop habitat models describing their distribution during the winters of 1999 and 2003 with the aim of visualising and quantifying the degree of spatial overlap between female fur seals and krill harvesting in South Georgia waters. We show that spatial distribution of fur seals around South Georgia is extensive, and that the krill fishery overlaps with small, highly localised areas of available fur seal habitat. From these findings we discuss the implications for management, and future work.


Polar Record ◽  
1978 ◽  
Vol 19 (119) ◽  
pp. 167-173 ◽  
Author(s):  
Anelio Aguayo L.

The purpose of this paper is to report on the present status of the small but growing population of the Antarctic Fur Seal Arctocephalus gazella in the South Shetland Islands (Fig 1). The previous history of the sealing of this species is well documented by O'Gorman (1961, 1963), Bonner and Laws (1964) and Bonner (1964,1968). The current status of this and other species of fur seals, and the species of sea lions and true seals in the Southern Hemisphere, has been summarized by Laws (1973a). Bonner (1968) has made natural history and population studies on Antarctic Fur Seals in South Georgia, and present research here is being carried out by Dr M. R. Payne and two other colleagues of the British Antarctic Survey (Laws, 1973b).


1992 ◽  
Vol 15 (1) ◽  
pp. 77
Author(s):  
P.D. Shaughnessy

Recent authoritative texts on Australian mammals include several pinniped species but most omit the Antarctic Fur Seal Arctocephalus gazella and Subantarctic Fur Seal A. tropicalis. The former species breeds at Heard Island; at Macquarie Island it breeds in territories with A. tropicalis. Information is tabulated on skulls of these two species held in Australian museums. It is argued that they should be included in comprehensive lists of Australian mammals.


Polar Biology ◽  
2007 ◽  
Vol 31 (5) ◽  
pp. 575-581 ◽  
Author(s):  
A. B. Makhado ◽  
M. N. Bester ◽  
S. P. Kirkman ◽  
P. A. Pistorius ◽  
J. W. H. Ferguson ◽  
...  

1999 ◽  
Vol 47 (6) ◽  
pp. 593 ◽  
Author(s):  
Simon D. Goldsworthy ◽  
Helen M. Crowley

The composition of milk collected from 36 antarctic (Arctocephalus gazella) and 17 subantarctic fur seals (A. tropicalis) breeding sympatrically at Macquarie Island was examined over the first 100 days of lactation in the 1990/91 season. The mean composition of milk in A. gazella and A. tropicalis was 41.3% and 44.6% water, 39.8% and 38.6% lipid, 18.1% and 16.1% protein, and the estimated gross energy content of milk was 19.9 and 18.9 kJ g–1, respectively. Neither the composition of milk nor its energy density differed significantly between species, despite a difference of 4–6 months in lactation length. Water content of milk could be used to predict lipid (r2 = 0.67) and protein (r2 = 0.57) content, but was most accurate at predicting gross energy content (r2 = 0.97). These relationships were the same for each species. The water content of milk decreased throughout the first 100 days of lactation in both species, while lipid, protein and energy content all increased. The addition of maternal mass into regression analysis with days post-partum increased the significance of models predicting the content of lipid and proteins in the milk, but not those predicting the water or gross energy content. Milk collected on the first day of 2-day attendance bouts had, on average, 9% greater lipid content, and 5% greater protein content than milk collected on the second day. The growth rates of subantarctic fur seal pups were significantly lower than those of antarctic fur seal pups over the first month of growth, suggesting that (despite similar milk composition, attendance patterns and diet of the two species of fur seal) the overall rates of energy transfer from mother to pup in subantarctic fur seals is lower than in antarctic fur seals.


1994 ◽  
Vol 28 (6) ◽  
pp. 375-380 ◽  
Author(s):  
H.M Malcolm ◽  
I.L Boyd ◽  
D Osborn ◽  
M.C French ◽  
P Freestone

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