Oceanographic factors influencing the distribution of South American fur seal, Arctocephalus australis around the Falkland Islands before the breeding season

Distribution of fur seals Arctocephalus australis has been studied in October 2007 on the western, southern and eastern Falkland shelves during the survey of spawning grounds of the red cod, Salilota australis. Fur seals presence/absence, numbers and sex were recorded at every oceanographic station. Animals were found foraging on the shelf edge south-west of the islands, in a productive zone with quasi-stationary eddies at a periphery of upwelling. It was also the zone of maximum abundance of lobster-krill, Munida spp.—an important food source of fur seals and aggregations of both red cod and blue whiting, Micromesistius australis. No fur seals were found in waters of the relative cold and saline Falkland Current as well as in the relatively warm, fresh and oxygen-rich waters of Argentine Drift. It allows supposing that position and extension of the foraging grounds are caused by oceanographic features determining distribution of prey species.

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Occurrence of South American fur seals Arctocephalus australis (Zimmermann, 1783) in San Matías Gulf, Patagonia, Argentina

Latin American Journal of Aquatic Research ◽

10.3856/vol41-issue3-fulltext-19 ◽

2016 ◽

Vol 41 (3) ◽

pp. 576-583

Author(s):

Guillermo Martín Svendsen ◽

Silvana Laura Dans ◽

Raúl Alberto González ◽

María Alejandra Romero ◽

Enrique Alberto Crespo

Keyword(s):

Physical Environment ◽

South American ◽

Population Recovery ◽

Drastic Reduction ◽

Atlantic Region ◽

Geographic Context ◽

Fur Seals ◽

Fur Seal ◽

Strategic Location ◽

First Time

The South American fur seal, Arctocephalus australis (SAFS) population suffered a drastic reduction due to commercial exploitation during the XVIII and XIX centuries. In the last decades a population recovery was detected in the Atlantic region. However, in this region, many aspects of the ecology of the SAFS, such as the post-reproductive dispersal of individuals, the location of feeding areas, and the movements of individuals between colonies on the boundaries of its distribution, are still unknown. Here, we report for the first time the occupation of San Matías Gulf (SMG, northern Patagonia, Argentina) by this species. We found that more than 1,600 SAFS used SMG between May and October (post-reproductive season) and detected a non-reproductive colony on Islote Lobos (41°24'S, 65°03'W). The presence of SAFS in SMG is recent and would be associated with an increase of the population on the Atlantic. The importance of SMG in the ecology of SAFS seems to lie on three factors: the strategic location in the geographic context of potential movements of individuals between distant colonies, the physical environment suitable for coastal settlements, and the availability of food resources.

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Diet of South American fur seals at the Falkland Islands

Marine Mammal Science ◽

10.1111/mms.12090 ◽

2013 ◽

Vol 30 (3) ◽

pp. 1210-1219 ◽

Cited By ~ 13

Author(s):

Alastair M. M. Baylis ◽

John P. Y. Arnould ◽

Iain J. Staniland

Keyword(s):

Falkland Islands ◽

South American ◽

Fur Seals

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Evidence of a genetic bottleneck in an El Niño affected population of South American fur seals, Arctocephalus australis

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315409000162 ◽

2009 ◽

Vol 89 (8) ◽

pp. 1717-1725 ◽

Cited By ~ 15

Author(s):

Larissa Rosa de Oliveira ◽

Diogo Meyer ◽

Joseph Hoffman ◽

Patricia Majluf ◽

João S. Morgante

Keyword(s):

Population Size ◽

El Niño ◽

El Nino ◽

Southern Oscillation ◽

Genetic Bottleneck ◽

South American ◽

Enso Events ◽

Fur Seals ◽

The Pacific ◽

Fur Seal

The South American fur seal, Arctocephalus australis, was one of the earliest otariid seals to be exploited by humans: at least 6000 years ago on the Atlantic coast and 4000 on the Pacific coast of South America. More than 750,000 fur seals were killed in Uruguay until 1991. However, a climatological phenomenon—the severe 1997–1998 El Niño Southern Oscillation (ENSO)—was responsible for the decline of 72% of the Peruvian fur seal population due to starvation as a consequence of warming of sea-surface temperatures and primary productivity reduction. Currently, there is no precise information on global population size or on the species' conservation status. The present study includes the first bottleneck test for the Pacific and Atlantic populations of A. australis based on the analysis of seven microsatellite loci. Genetic bottleneck compromises the evolutionary potential of a population to respond to environmental changes. The perspective becomes even more alarming due to current global warming models that predict stronger and more frequent ENSO events in the future. Our analysis found moderate support for deviation from neutrality–equilibrium for the Pacific population of fur seals and none for the Atlantic population. This difference among population reflects different demographic histories, and is consistent with a greater reduction in population size in the Pacific. Such an event could be a result of the synergic effects of recurrent ENSO events and the anthropogenic impact (sealing and prey overfishing) on this population.

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Spring and summer prey of the Juan Fernández fur seal, Arctocephalus philippii

Canadian Journal of Zoology ◽

10.1139/z95-170 ◽

1995 ◽

Vol 73 (8) ◽

pp. 1444-1452 ◽

Cited By ~ 14

Author(s):

Hugo Ochoa Acuña ◽

John M. Francis

Keyword(s):

Prey Species ◽

Narrow Range ◽

Prey Availability ◽

Subadult Male ◽

Marine Communities ◽

Fur Seals ◽

Fur Seal ◽

Pelagic Environment ◽

One Year ◽

Made In

The composition of Juan Fernández fur seal (Arctocephalus philippii) prey was assessed through analysis of 437 scats collected during five reproductive seasons (1987–1991). In total, 14 collections were analyzed and, based on 4172 fish otoliths and cephalopod beaks, 13 prey species were identified. The occurrences of fish families were as follows: Myctophidae (80.3%), Scomberesocidae (10%), Carangidae (9.5%), Engraulidae (1.0%), and Bathylagidae (0.7%). Cephalopod families included Onychoteuthidae (27.1%), Ommastrephidae (3.7%), and Tremoctopodidae (0.7%). In one year when data were available, Symbolophorus sp. B was found more frequently in subadult male and juvenile scats than in female scats (P < 0.004). Female scats contained larger numbers of the squid Onychoteuthis banksi than did subadult male and juvenile scats (P < 0.0001). When collections made in early December were compared, the occurrence of O. banksi in subadult male and juvenile scats differed significantly between years (P < 0.0001). Within-year variations in occurrence were significant only for O. banksi in 1989. The data suggest that the narrow range of species preyed upon by Juan Fernández fur seals is unlikely to represent specialization, but is probably related to overall prey availability in the pelagic environment. Although information on marine communities in this area is limited, it is possible to relate observed prey shifts to variations in sea-surface temperature.

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New host and geographical records for Parafilaroides normani (Nematoda: Filaroididae) Dailey, 2009 in South American fur seal, Arctocephalus australis, from southern Brazil

Journal of Helminthology ◽

10.1017/s0022149x20000826 ◽

2020 ◽

Vol 94 ◽

Author(s):

J. Echenique ◽

E. Pereira ◽

J. Prado ◽

A.L. Schild ◽

A.L. Valente

Keyword(s):

Additional Data ◽

First Record ◽

Common Finding ◽

South American ◽

Southern Coast ◽

New Host ◽

Biogeographical Distribution ◽

Fur Seals ◽

Fur Seal ◽

Pinniped Species

Abstract Lungworms are a common finding in seals and fur seals around the world. However, from existing records, the biogeographical distribution of filaroid helminths appears to be restricted, and these parasites are endemic in only certain areas and species, mainly in the Northern Hemisphere. The occurrence of infection in pinniped species in the Southern Hemisphere is scarce. The objective of this work is to verify the prevalence of lungworms in Arctocephalus australis in waters off the southern coast of Brazil. Twenty subadult specimens of A. australis found recently dead on the southern coast of Brazil were necropsied and their lungs were examined. Parasitic cysts were found in only one specimen (prevalence of 5%). The helminths were morphologically identified as Parafilaroides normani (Metastrongyloidea: Filaroididae). This helminth species has been reported in pinnipeds from Australia, New Zealand and South Africa. This is the first record of P. normani in A. australis and for the western South Atlantic, providing additional data regarding the biogeographic distribution of the parasite.

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Protecting Fur Seals During Spill Response: Lessons from the San Jorge (Uruguay) Oil Spill

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1999-1-467 ◽

1999 ◽

Vol 1999 (1) ◽

pp. 467-470 ◽

Cited By ~ 3

Author(s):

Alan J. Mearns ◽

Ed Levine ◽

Ruth Yender ◽

Douglas Helton ◽

Thomas Loughlin

Keyword(s):

Oil Spill ◽

Waste Materials ◽

Peat Moss ◽

South American ◽

Hand Tools ◽

Fur Seals ◽

Fur Seal ◽

Small Hand ◽

International Experts ◽

Crude Oil Spill

ABSTRACT Nearly 5,000 2- to 3-month old South American fur seal pups were oiled and/or died as a result of a February 1997, 5,000-metric ton crude oil spill near Punta del Este, Uruguay. After consultation with international experts, the Uruguayan government commissioned small teams (three to five people) of trained military technicians (totaling 30–45 people) who cleaned most of the heavily oiled areas manually using buckets, shovels, small hand tools, specially-treated peat moss, and small driftwood fires. Waste materials were bagged and transported to a mainland facility for treatment. Dead pups were placed into well-marked rocky cemeteries and treated with quicklime. Despite the mortality, the low-technology response was a success because it added no additional injury to the affected populations. Lessons from this international experience are being used to develop cleanup and protection plans for other fur seal rookery areas, including Alaska's ?ribilof Islands.

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Maternal aggression in the South American fur seal in Peru

Canadian Journal of Zoology ◽

10.1139/z92-048 ◽

1992 ◽

Vol 70 (2) ◽

pp. 320-325 ◽

Cited By ~ 31

Author(s):

Robert Harcourt

Keyword(s):

Post Partum ◽

Female Aggression ◽

South American ◽

The South ◽

Maternal Aggression ◽

Sea Lions ◽

Fur Seals ◽

Fur Seal ◽

Maternal Defense ◽

Pup Mortality

Maternal aggression was examined with regard to its role in maternal defense of offspring in the South American fur seal (Arctocephalus australis) at Punta San Juan, Peru (15°22′S, 75°12′W). Female fur seals' responses to conspecifics and to predatory southern sea lions (Otaria byronia) were examined pre- and post-partum. Although the defense of offspring from predators may be expected to be a major component of maternal care, mothers rarely defended their offspring from raiding sea lions, possibly due to the high risks involved in attacking a large and potentially very dangerous predator. The costs of defending the pup from sea lions appeared to outweigh the potential benefit of increased survival of the pup, due to the already high pup mortality at the site. Maternal defense from conspecifics may also be a possible function of female aggression. Females with newborn pups were more aggressive towards other females than were females without pups, particularly during the perinatal attendance period. They threatened a higher proportion of approaching females and won more aggressive encounters postpartum. However, mothers of surviving pups did not appear to be any more aggressive, their pups did not receive any fewer threats from unrelated females, nor did they reside in areas of less aggression, than mothers whose pups died. Aggression towards male conspecifics appeared to serve a further purpose, as females threatened approaching adult and subadult males regardless of whether the females had a pup. Unlike colonially breeding phocid pinnipeds, there seems to be no correlation between increased maternal aggression and neonate survival in the South American fur seal. This may be because females have to leave their offspring to forage when the offspring are still vulnerable to attack by unrelated conspecifics. Alternatively, maternal aggression may have been subjected to such intense selection that although it is responsible for increased pup mortality at the site, there is insufficient variability to measure differential consequences.

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