scholarly journals Comparative analysis of the diet of Arctocephalus gazella (Pinnipedia), at two localities of the South Shetland Islands, with emphasis on the fish component

2021 ◽  
Vol 111 ◽  
Author(s):  
Mariana Descalzo ◽  
Gustavo A. Daneri ◽  
Javier Negrete ◽  
Aldo Corbalán ◽  
Esteban Barrera-Oro
Keyword(s):  
Negative Impact ◽  
Feeding Habits ◽  
Euphausia Superba ◽  
South Shetland Islands ◽  
Arctocephalus Gazella ◽  
The South ◽  
Scotia Sea ◽  
Shetland Islands ◽  
Important Prey ◽  
Fur Seals

ABSTRACT We studied the diet of non-breeding male Antarctic fur Seals Arctocephalus gazella (Peters, 1875) at two different localities of the South Shetland Islands: Stranger Point, King George Island/Isla 25 de Mayo and Duthoit Point, Nelson Island, by the analysis of 65 faecal samples collected in February 2012. Overall, Antarctic krill Euphausia superba (Dana, 1850) and fish were the main prey taxa followed by penguins and cephalopods. Myctophids were dominant among fish; Gymnoscopelus nicholsi (Gilbert, 1911) was the most important prey species at both sampling sites, followed by Electrona antarctica (Gunther, 1878) at Stranger Point and by the nototheniid Pleuragramma antarctica (Boulenger, 1902) at Duthoit Point. The relative similarity found in the dietary composition of fur seals from both locations suggest they might have been sharing common feeding areas. Our results were compared with those reported in the literature for different localities of the South Shetland Islands and the Scotia Sea region. The absence of formerly harvested demersal notothenioid species in the diet of fur seals may reflect the negative impact that commercial fisheries had on some fish populations and supports the importance of implementing long-term monitoring studies on the feeding habits of A. gazella in the area.

Stable isotopes identify an ontogenetic niche expansion in Antarctic krill (Euphausia superba) from the South Shetland Islands, Antarctica

2013 ◽  
Vol 160 (6) ◽  
pp. 1311-1323 ◽  
Author(s):  
Michael J. Polito ◽  
Christian S. Reiss ◽  
Wayne Z. Trivelpiece ◽  
William P. Patterson ◽  
Steven D. Emslie
Keyword(s):  
Stable Isotopes ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
South Shetland Islands ◽  
The South ◽  
Niche Expansion ◽  
Shetland Islands ◽  
Ontogenetic Niche ◽  
Antarctic Krill Euphausia Superba

Genetic diversity and structure of Euphausia superba in the South Shetland Islands using the mitochondrial ND6 gene

Crustaceana ◽  
2019 ◽  
Vol 92 (11-12) ◽  
pp. 1295-1309
Author(s):  
Yao Dong ◽  
Guangrui Qi ◽  
Chunlei Feng ◽  
Wei Wang ◽  
Fengying Zhang ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Demographic History ◽  
Scientific Information ◽  
Euphausia Superba ◽  
South Shetland Islands ◽  
Sudden Expansion ◽  
The South ◽  
Shetland Islands ◽  
Fisheries Resources ◽  
Genetic Diversity And Structure

Abstract Euphausia superba is an abundant element in the marine plankton on the planet. Despite substantial research on this species, there is no comprehensive understanding of the population genetics of E. superba yet. In this study, the ND6 gene was used to assess the genetic variation in E. superba. In the South Shetland Islands, the population of E. superba shows abundant genetic variation, but we found a lack of genetic structure. An analysis of the demographic history suggested that a sudden expansion has been responsible for its high biomass. Our study could not only broaden our comprehension of E. superba, but also provide more scientific information on fisheries resources exploitation, biodiversity conservation and the maintenance of a proper ecological balance.

Spring and summer predation on fish by the Antarctic fur seal, Arctocephalus gazella, at King George Island, South Shetland Islands

1999 ◽  
Vol 77 (7) ◽  
pp. 1157-1160 ◽  
Author(s):  
G A Daneri ◽  
A R Carlini
Keyword(s):  
Fish Species ◽  
Relative Proportion ◽  
South Shetland Islands ◽  
Arctocephalus Gazella ◽  
King George Island ◽  
Pleuragramma Antarcticum ◽  
Fish Prey ◽  
Austral Spring ◽  
Shetland Islands ◽  
Fur Seals

The fish component of the diet of nonbreeding male Antarctic fur seals, Arctocephalus gazella, was analyzed from 70 scats collected at Stranger Point, King George Island, South Shetland Islands, during the austral spring (n = 36) and summer (n = 34) of 1993-1994. Fish occurred in approximately 70% of scats that contained food remains irrespective of season. In spring, the main fish prey were Electrona antarctica, Pleuragramma antarcticum, and Notolepis coatsi, which together gave two-thirds of the 110 otoliths recovered. In summer, 457 otoliths were retrieved; the most frequent and abundant species were Gymnoscopelus nicholsi, E. antarctica, and P. antarcticum, which represented over 80% of the otoliths recovered. A substantial increase in the amount of fish ingested by fur seals occurred from spring to summer concomitant with a change in the relative proportion of fish taxa. Most fish species identified are pelagic and feed on krill. During the study period, commercial fishing in the area was not based upon any of the fish species identified.

The Maximum Ice Extent on Island Groups in the Scotia Sea, Antarctica

1977 ◽  
Vol 7 (2) ◽  
pp. 268-282 ◽  
Author(s):  
D.E. Sugden ◽  
C.M. Clapperton
Keyword(s):  
Ice Cover ◽  
South Shetland Islands ◽  
Falkland Islands ◽  
The South ◽  
Scotia Sea ◽  
Shetland Islands ◽  
South Georgia ◽  
Orkney Islands ◽  
Ice Caps ◽  
The Antarctic

Evidence is presented for a more extensive ice cover over South Georgia, the South Orkney Islands, the South Shetland Islands, and the tip of the Antarctic Peninsula. Ice extended across the adjacent submarine shelves to a depth of 200 m below present sea level. Troughs cut into the submarine shelves by ice streams or outlet glaciers and ice-scoured features on the shelf areas suggest that the ice caps were warm-based. The South Shetland Islands appear not to have been overrun by continental ice. Geomorphological evidence in two island groups suggests that the maximum ice cover, which was responsible for the bulk of glacial erosion, predates at least one full glaciation. Subsequently there was a marine interval and then a glaciation which overran all of the lowlying peninsulas. The Falkland Islands, only 2° of latitude north of South Georgia, were never covered by an ice cap and supported only a few slightly enlarged cirque glaciers. This suggests that the major oceanographic and atmospheric boundary represented by the Antarctic Convergence, which is presently situated between the Falkland Islands and South Georgia, has remained in a similar position throughout the glacial age. Its position is probably bathymetrically controlled.

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