Interspecific and intraspecific differences in the diets of Fur seals, Arctocephalus species (Pinnipedia: Otariidae) at Macquarie Island.

1990 ◽  
Vol 13 (2) ◽  
pp. 193
Author(s):  
K. Green ◽  
R. Williams ◽  
K.A. asyde ◽  
P.D. Burton HR. and Shaughnessy
Keyword(s):  
Food Resources ◽  
Fish Diet ◽  
Macquarie Island ◽  
Fur Seals ◽  
Heard Island ◽  
Fish Remains

Between November 1988 and March 1989, scats were collected from three species of fur seals (Arctocephalus forsteri, A. gazella and A. tropicalis) at the northern end of Macquarie Island and from A. forsteri between January and March 1989 at the southern end. All fed mainly on fish. For A. gazella/A. tropicalis an average 99.2 % of scats in monthly collections contained fish remains, while for A. forsteri the figure for North Head was 100 % and for Hurd Point was 94.9 %. Arctocephalus forsteri at Hurd Point took less fish and more penguins than at North Head and there were significant differences in the composition of the fish diet in two of three months. At North Head, the fish diet of A. gazella/A. tropicalis differed significantly from that of A. forsteri in three of the five months studied . Food resources for fur seals around Macquarie Island are considered to be less available than they are around Heard Island.

Accumulation of Fishing Debris, Plastic Litter, and Other Artefacts, on Heard and Macquarie Islands in the Southern Ocean

1991 ◽  
Vol 18 (3) ◽  
pp. 249-254 ◽  
Author(s):  
David J. Slip ◽  
Harry R. Burton
Keyword(s):  
Southern Ocean ◽  
Catchment Area ◽  
Marine Debris ◽  
Minimum Rate ◽  
Macquarie Island ◽  
Fur Seals ◽  
Heard Island

Sections of coastline of Heard and Macquarie Islands were surveyed for marine debris in the summer of 1987–88 and 1989, respectively. These surveys were carried out at the same sites as previous surveys in 1986–87 at Heard Island, and in 1988 at Macquarie Island. The minimum rate of artefact accumulation was 13 objects per km of shoreline per year for Heard Island, and 90 objects per km of shoreline per year for Macquarie Island. Drift-cards, released from known locations and collected on the two islands, show a similar artefact catchment area.Plastic litter was a major component of the debris at both islands. Fisheries-related debris accounted for 40% of all artefacts on Heard Island, compared with 29% on Macquarie Island. Entanglement of Fur Seals appears to be more common at Heard Island, while plastic ingestion by seabirds appears to be more common at Macquarie Island.

scholarly journals The diet of Antarctic fur seals Arctocephalus gazella (Peters) during the breeding season at Heard Island

1989 ◽  
Vol 1 (4) ◽  
pp. 317-324 ◽  
Author(s):  
K. Green ◽  
H.R. Burton ◽  
R. Williams
Keyword(s):  
Summer Season ◽  
High Availability ◽  
Population Increase ◽  
Arctocephalus Gazella ◽  
Shelf Area ◽  
Fur Seals ◽  
Heard Island ◽  
Middle Period ◽  
Fish Remains ◽  
Antarctic Fur Seals

Between September 1987 and February 1988, Antarctic fur seals Arctocephalus gazella (Peters) at Heard Island fed mainly on fish with an average 95.2% of scats in monthly collections containing fish remains. Pelagic myctophids constituted more than 50% of fish taken by fur seals at the beginning of the summer season and again at the end when there was an influx of non-breeding male seals. During the middle period from October to December, fish from the surrounding shelf area comprised the bulk of the diet. These included various benthic nototheniid species, the bentho-pelagic ice fish Champsocephalus gunnari Lönnberg and skate (Bathyraja spp.), the latter being found in over 60% of scats in October and November. The population of Antarctic fur seals at Heard Island is increasing at about the same rate as at South Georgia. There the increase is thought to be due to the high availability of krill E. superba, but in the present study no euphausiid remains were found, so the increasing population at Heard Island has been supported on a diet of fish. Whether this population increase can be sustained in future on a diet of fish is arguable. Trial fishing around Heard Island indicates that one of the major dietary items of the seals (C. gunnari) is of probable commercial importance and therefore any plans for the establishment of a fishery on Heard Island grounds must be considered in this light.

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-seals at Heard Island: recovery from past exploitation?

1988 ◽  
pp. 71-77 ◽  
Author(s):  
P. D. Shaughnessy ◽  
G. L. Shaughnessy ◽  
P. L. Keage
Keyword(s):  
Fur Seals ◽  
Heard Island

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.

Relationships among water quality, food resources, fish diet and fish growth in polyculture ponds: A multivariate approach

Aquaculture ◽  
2008 ◽  
Vol 275 (1-4) ◽  
pp. 108-115 ◽  
Author(s):  
M. Mustafizur Rahman ◽  
Leopold A.J. Nagelkerke ◽  
Marc C.J. Verdegem ◽  
M. Abdul Wahab ◽  
Johan A.J. Verreth
Keyword(s):  
Water Quality ◽  
Food Resources ◽  
Fish Growth ◽  
Fish Diet ◽  
Multivariate Approach ◽  
Quality Food

Vitamin A plasma kinetics in northern fur seals (Callorhinus ursinus), using vitamin A2 as a tracer

1995 ◽  
Vol 73 (1) ◽  
pp. 10-14 ◽  
Author(s):  
Liza M. Mazzaro ◽  
J. Lawrence Dunn ◽  
Harold C. Furr ◽  
Richard M. Clark
Keyword(s):  
Vitamin A ◽  
The Body ◽  
Plasma Vitamin ◽  
Maximum Plasma ◽  
Callorhinus Ursinus ◽  
Base Line ◽  
Fish Diet ◽  
Plasma Kinetics ◽  
Fur Seals ◽  
Northern Fur Seals

Vitamin A2 (3,4-didehydroretinol), a natural analog of retinol, was used to determine the plasma kinetics of vitamin A in two northern fur seals (Callorhinus ursinus) receiving two levels of vitamin A supplements. After a single oral dose, the time required to reach maximum plasma vitamin A2 concentration for both subjects was approximately 2 h, which is much less than the 8–12 h observed with humans. The level of vitamin A supplementation did not affect base-line plasma retinol concentrations or plasma kinetics. The mean sojourn time, the average time spent by a molecule of vitamin A in the body before being lost, was 40 days for one animal and 73 days for the other. The daily vitamin A requirement estimated from the disposal rate was 0.32–0.64 μmol per day for the two animals. The presumed upper safe level was calculated at 1.3–6.4 μmol vitamin A per day. It would appear that the fish diet commonly provided to these animals can meet their vitamin A requirements. Supplementation may only be warranted to offset vitamin loss during storage and handling of the food. However, a conservative approach to supplementation should be used, as chronic vitamin A toxicity is a danger.

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