scholarly journals Winter distribution of juvenile and sub-adult male Antarctic fur seals (Arctocephalus gazella) along the western Antarctic Peninsula

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David March ◽  
Massimiliano Drago ◽  
Manel Gazo ◽  
Mariluz Parga ◽  
Diego Rita ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Adult Male ◽  
Antarctic Krill ◽  
South Shetland Islands ◽  
Distribution Area ◽  
Arctocephalus Gazella ◽  
Western Antarctic Peninsula ◽  
Adult Males ◽  
Fur Seals ◽  
Antarctic Fur Seals

AbstractDetailed knowledge of habitat use by marine megafauna is critical to understand their ecological roles and for the adequate management of marine resources. Antarctic fur seals (Arctocephalus gazella) inhabiting the Atlantic sector of the Southern Ocean prey largely on Antarctic krill (Euphausia superba) and play a central role in managing the krill fishery. Here, we assessed the demographic structure of three post-mating, early moult male haul-outs in the South Shetland Islands in early March and calculated the relative contribution of juveniles (1–4 years old) and sub-adult males (5–6 years) to the population remaining in maritime Antarctica after the breeding season. We also satellite tagged 11 juvenile males and four sub-adult males to analyze their movements and develop a species distribution model including both age classes. Our results highlighted the dominance of young individuals in the male population, revealed that they do not behave as central place foragers and identified key environmental drivers that affected their distribution at-sea throughout winter. Predicted potential foraging habitat overlapped highly with the known distribution of Antarctic krill, and identified the waters off the western Antarctic Peninsula and the Scotia Sea as the core of the distribution area of juvenile and sub-adult male Antarctic fur seals in winter. This pattern is similar to that of adult males but totally different from that of adult females, as the latter overwinter in areas at latitude 45–55° S. This segregation has implications for the ecology and management of the krill fishery.

Dispersal of male and female Antarctic fur seals (Arctocephalus gazella)

1998 ◽  
Vol 55 (4) ◽  
pp. 845-852 ◽  
Author(s):  
I L Boyd ◽  
D J McCafferty ◽  
K Reid ◽  
R Taylor ◽  
T R Walker
Keyword(s):  
Arctocephalus Gazella ◽  
Adult Males ◽  
The South ◽  
Male And Female ◽  
Breeding Sites ◽  
South Georgia ◽  
Orkney Islands ◽  
Fur Seals ◽  
South Orkney Islands ◽  
Antarctic Fur Seals

This study examined the foraging locations of adult male and female Antarctic fur seals (Arctocephalus gazella) in the Scotia Sea during the postbreeding period. Satellite transmitters were used to track adult males and females and to obtain information about dive depths. Male fur seals migrated away from the breeding area during the postbreeding period whereas females remained close to the breeding grounds and foraged in the same area during two consecutive years. The most intensive foraging by females was associated with the edge of the continental shelf of South Georgia. Males dived deeper than females. Counts of males at South Georgia and at the South Orkney Islands support the result from satellite tracking data showing that males move from South Georgia to the South Orkney Islands at the end of the breeding season. Unlike males, females were limited in their foraging range by the necessity to return to feed dependent young, so breeding sites are likely to be located close to foraging areas that are optimal for females. Locations used for feeding by females were avoided by males, either because they were suboptimal for males or because foraging by females at South Georgia causes local depletion of food, and males, which have the option to forage further afield, can forage more successfully in regions where there are no females. Comparison with fisheries data also suggests that these fur seals are targeting the most abundant exploitable prey.

scholarly journals The Rapid Population Collapse of a Key Marine Predator in the Northern Antarctic Peninsula Endangers Genetic Diversity and Resilience to Climate Change

2022 ◽  
Vol 8 ◽  
Author(s):  
Douglas J. Krause ◽  
Carolina A. Bonin ◽  
Michael E. Goebel ◽  
Christian S. Reiss ◽  
George M. Watters
Keyword(s):  
Climate Change ◽  
Genetic Diversity ◽  
Antarctic Peninsula ◽  
Conservation Status ◽  
South Shetland Islands ◽  
Population Declines ◽  
Marine Predator ◽  
Fur Seals ◽  
Precipitous Decline ◽  
Antarctic Fur Seals

Antarctic fur seals (AFS) are an ecologically important predator and a focal indicator species for ecosystem-based Antarctic fisheries management. This species suffered intensive anthropogenic exploitation until the early 1900s, but recolonized most of its former distribution, including the southern-most colony at Cape Shirreff, South Shetland Islands (SSI). The IUCN describes a single, global AFS population of least concern; however, extensive genetic analyses clearly identify four distinct breeding stocks, including one in the SSI. To update the population status of SSI AFS, we analyzed 20 years of field-based data including population counts, body size and condition, natality, recruitment, foraging behaviors, return rates, and pup mortality at the largest SSI colony. Our findings show a precipitous decline in AFS abundance (86% decrease since 2007), likely driven by leopard seal predation (increasing since 2001, p << 0.001) and potentially worsening summer foraging conditions. We estimated that leopard seals consumed an average of 69.3% (range: 50.3–80.9%) of all AFS pups born each year since 2010. AFS foraging-trip durations, an index of their foraging habitat quality, were consistent with decreasing krill and fish availability. Significant improvement in the age-specific over-winter body condition of AFS indicates that observed population declines are driven by processes local to the northern Antarctic Peninsula. The loss of SSI AFS would substantially reduce the genetic diversity of the species, and decrease its resilience to climate change. There is an urgent need to reevaluate the conservation status of Antarctic fur seals, particularly for the rapidly declining SSI population.

Antarctic Fur Seals (Arctocephalus gazella) Observed Predating Adélie (Pygoscelis adeliae) and Chinstrap Penguins (P. antarctica), Antarctic Peninsula

2008 ◽  
Vol 34 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Ingrid N. Visser ◽  
Matt P. Drennan ◽  
Richard W. White ◽  
Stephen F. MacLean ◽  
Lisa C. Lagerstrom ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Arctocephalus Gazella ◽  
Pygoscelis Adeliae ◽  
Fur Seals ◽  
Antarctic Fur Seals

scholarly journals Wintertime overlaps between female Antarctic fur seals (Arctocephalus gazella) and the krill fishery at South Georgia, South Atlantic

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
Keyword(s):  
Antarctic Krill ◽  
Euphausia Superba ◽  
Arctocephalus Gazella ◽  
Habitat Models ◽  
South Georgia ◽  
Fur Seals ◽  
Fur Seal ◽  
Ice Edge ◽  
Future Work ◽  
Antarctic Fur Seals

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.

Fur seals, whales and tourists: a commercial history of Deception Island, Antarctica

Polar Record ◽  
2009 ◽  
Vol 46 (3) ◽  
pp. 210-221 ◽  
Author(s):  
J. Stephen Dibbern
Keyword(s):  
South Shetland Islands ◽  
Deception Island ◽  
Commercial Activity ◽  
Early 19Th Century ◽  
Cruise Industry ◽  
Shetland Islands ◽  
Fur Seals ◽  
History Of ◽  
The Antarctic ◽  
Antarctic Fur Seals

ABSTRACTDeception Island in the South Shetland Islands was the site of some of the earliest commercial activity to be carried out in the Antarctic with the early 19th century hunting of Antarctic fur seals. Nearly a century later it was the site of the most extensive anchorage for the reconstructed ships and ocean liners used as non-pelagic whale processing factories. Deception was also the site of what is the only successful land based commercial activity in Antarctic history. The Hektor whaling station operated in Whalers Bay from 1912 until 1931. Most of the remains of the station have now been obliterated by the volcanic activity that occurred in the late 1960s and 1970. By the later part of the twentieth century Deception Island had become a regular stop for the growing Antarctic tourist cruise industry. No other place in Antarctica has been so thoroughly identified with commercial activity.

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