The composition of the milk of antarctic (Arctocephalus gazella) and subantarctic (A. tropicalis) fur seals at Macquarie Island

1999 ◽  
Vol 47 (6) ◽  
pp. 593 ◽  
Author(s):  
Simon D. Goldsworthy ◽  
Helen M. Crowley
Keyword(s):  
Water Content ◽  
Energy Content ◽  
Post Partum ◽  
Milk Composition ◽  
Arctocephalus Gazella ◽  
Macquarie Island ◽  
Fur Seals ◽  
Fur Seal ◽  
Gross Energy ◽  
Subantarctic Fur Seals

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.

New mammals recognised for Australia - Antarctic and Subantarctic Fur Seals Arctocephalus species

1992 ◽  
Vol 15 (1) ◽  
pp. 77
Author(s):  
P.D. Shaughnessy
Keyword(s):  
Arctocephalus Gazella ◽  
Antarctic Fur Seal ◽  
Macquarie Island ◽  
Fur Seals ◽  
Fur Seal ◽  
Heard Island ◽  
Pinniped Species ◽  
The Antarctic ◽  
Subantarctic Fur Seals

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.

Fur seal skull from sealers' quarters at Sandy Bay, Macquarie Island, Southern Ocean

Polar Record ◽  
1991 ◽  
Vol 27 (162) ◽  
pp. 245-248 ◽  
Author(s):  
K. Townrow ◽  
P. D. Shaughnessy
Keyword(s):  
Southern Ocean ◽  
Arctocephalus Gazella ◽  
Archaeological Excavation ◽  
Antarctic Fur Seal ◽  
Macquarie Island ◽  
Fur Seals ◽  
Fur Seal ◽  
Antarctic Research ◽  
The Antarctic ◽  
Specific Identity

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.

Attendance behaviour of Antarctic and subantarctic fur seal females at Marion Island

1990 ◽  
Vol 2 (4) ◽  
pp. 309-312 ◽  
Author(s):  
Marthán N. Bester ◽  
Peter A. Bartlett
Keyword(s):  
Arctocephalus Gazella ◽  
Marion Island ◽  
Fur Seals ◽  
Fur Seal ◽  
Lactating Females ◽  
The Mean ◽  
Temperate Environment ◽  
The Difference ◽  
Antarctic Fur Seals ◽  
Subantarctic Fur Seals

The female attendance behaviour of Antarctic fur seals (Arctocephalus gazella) and subantarctic fur seals (A.tropicalis), which breed sympatrically on subantarctic Marion Island, was investigated. Over the same period after the breeding season, the mean duration of feeding trips to sea, and percentage of time spent at sea, did not differ significantly between lactating females of the two species. The difference in mean duration of shore visits was significant and the longer onshore attendance of A. tropicalis probably related to the lower demand by their pups which grow at a slower rate. The subpolar maternal adaptations of A. gazella were unchanged under the more temperate environment at Marion Island, and it remains to be established unequivocally whether conditions there are limiting to the species.

The foraging ecology of two sympatric fur seal species, Arctocephalus gazella and Arctocephalus tropicalis, at Macquarie Island during the austral summer

2002 ◽  
Vol 53 (7) ◽  
pp. 1071 ◽  
Author(s):  
S. A. Robinson ◽  
S. G. Goldsworthy ◽  
J. van den Hoff ◽  
M. A. Hindell
Keyword(s):  
Foraging Behaviour ◽  
Foraging Ecology ◽  
Austral Summer ◽  
Sympatric Species ◽  
Arctocephalus Gazella ◽  
Macquarie Island ◽  
Fur Seals ◽  
Fur Seal ◽  
Marine Environmental ◽  
Arctocephalus Tropicalis

Antarctic Arctocephalus gazella and subantarctic Arctocephalus tropicalis fur seals breed sympatrically at Macquarie Island. The two species have different lactation strategies, the former rearing its pup in 4 months and the latter taking 10 months. The diet and at-sea foraging behaviour of these sympatric species was compared during the austral summer period when their pup rearing period overlapped. The prey of the two fur seal species was very similar, with fish dominating the diet. The myctophid, Electrona subaspera, was the main prey item (93.9%) in all months of the study. There were no major differences in the diving behaviour between species. Both species foraged north of the island parallel to the Macquarie Ridge. Foraging activity was concentrated at two sites: (i) within 30�km north of the island; and (ii) at 60 km north. Most locations for overnight foraging trips were within 10 km of the colonies. The different lactation strategies of A. gazella and A. tropicalis allowed for flexibility in foraging behaviour. At Macquarie Island, the local marine environmental conditions have resulted in similar foraging behaviour for both species.

Records of vagrant fur seals (family Otariidae) in South Australia

2014 ◽  
Vol 36 (2) ◽  
pp. 154 ◽  
Author(s):  
Peter D. Shaughnessy ◽  
Catherine M. Kemper ◽  
David Stemmer ◽  
Jane McKenzie
Keyword(s):  
New Zealand ◽  
South Australia ◽  
The South ◽  
South Indian Ocean ◽  
Fur Seals ◽  
South Indian ◽  
Fur Seal ◽  
New Zealand Fur Seal ◽  
The Antarctic ◽  
Subantarctic Fur Seals

Two fur seal species breed on the southern coast of Australia: the Australian fur seal (Arctocephalus pusillus doriferus) and the New Zealand fur seal (A. forsteri). Two other species are vagrants: the subantarctic fur seal (A. tropicalis) and the Antarctic fur seal (A. gazella). We document records of vagrant fur seals in South Australia from 1982 to 2012 based primarily on records from the South Australian Museum. There were 86 subantarctic fur seals: 49 specimens and 37 sightings. Most (77%) were recorded from July to October and 83% of all records were juveniles. All but two specimens were collected between July and November. Sightings were prevalent during the same period, but there were also nine sightings during summer (December–February), several of healthy-looking adults. Notable concentrations were near Victor Harbor, on Kangaroo Island and Eyre Peninsula. Likely sources of subantarctic fur seals seen in South Australia are Macquarie and Amsterdam Islands in the South Indian Ocean, ~2700 km south-east and 5200 km west of SA, respectively. There were two sightings of Antarctic fur seals, both of adults, on Kangaroo Island at New Zealand fur seal breeding colonies. Records of this species for continental Australia and nearby islands are infrequent.

Milking Strategy in Subantarctic Fur Seals Arctocephalus tropicalis Breeding on Amsterdam Island: Evidence from Changes in Milk Composition

2001 ◽  
Vol 74 (4) ◽  
pp. 548-559 ◽  
Author(s):  
Jean‐Yves Georges ◽  
René Groscolas ◽  
Christophe Guinet ◽  
Jean‐Patrice Robin
Keyword(s):  
Milk Composition ◽  
Fur Seals ◽  
Subantarctic Fur Seals ◽  
Arctocephalus Tropicalis

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
Keyword(s):  
Arctocephalus Gazella ◽  
South Georgia ◽  
Fur Seals ◽  
Fur Seal ◽  
Total Fish ◽  
Fish Remains ◽  
Gobionotothen Gibberifrons ◽  
Lepidonotothen Larseni ◽  
The Antarctic ◽  
Fish Otoliths

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.

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