|Scientific Name:||Arctocephalus pusillus (Schreber, 1775)|
|Infra-specific Taxa Assessed:|
Phoca pusilla Schreber, 1775
The two recognized subspecies of Afro-Australian Fur Seal, the Cape Fur Seal (Arctocephalus pusillus pusillus) and the Australian Fur Seal (A. p. doriferus), are almost identical in both anatomy and behaviour (Warnecke and Shaughnessy 1985). Repenning et al. (1971) accorded them subspecific status based on one cranial character and separate geographic ranges. Very low genetic divergence indicates that they split relatively recently, with the Australian subspecies being the more recently established (Lento et al. 1997, Wynen et al. 2001), possibly derived as a consequence of late Pleistocene/Holocene (~12,000 years before present) migration events from southern Africa to southern Australia via west-wind drift across the Indian Ocean (Deméré et al. 2003, Lancaster et al. 2010, Wynen et al. 2001).
|Red List Category & Criteria:||Least Concern ver 3.1|
|Contributor(s):||Kirkman, S., Meÿer, M. & Roux, J.-P|
|Facilitator/Compiler(s):||Lowry, L., Ahonen, H., Pollock, C.M., Chiozza, F. & Battistoni, A.|
Abundance of Cape Fur Seals is estimated to be approximately 2,000,000 animals, while that of Australian Fur Seals is 120,000. No subpopulations exist for either subspecies and no localities are isolated from any others. Total abundance for each subspecies is estimated to have increased over the past three generations. Cape Fur Seal abundance has been stable over the past two generations while Australian Fur Seals increased up to 2007, but have since experienced a 6% mean annual decrease in pup production. It is unknown whether this apparent reduction is due to a poor pupping season in 2013/14, or if it represents a real decline in the population. Fluctuations in the abundance of Cape Fur Seals have been seen in the southern Namibian rookeries as a result of poor environmental conditions affecting prey populations. No major threats currently put any of the breeding sites at risk of extinction. Australian Fur Seals are subject to persistent bycatch mortality from trawl fisheries in part of their range, and both subspecies may be affected by global climate change should it have impacts upon their abiotic environment or prey species. Smaller island rookeries of both subspecies are possibly more vulnerable to such changes. The Afro-Australian Fur Seal does not meet the IUCN criteria for any threatened category and should be listed as Least Concern.
|Previously published Red List assessments:|
Cape Fur Seals range along the southwestern and southern coasts of Africa, from Ilha dos Tigres in southern Angola, along the coast of Namibia to Algoa Bay in South Africa (Kirkman et al. 2013, Oosthuizen 1991). Sightings of vagrants are limited to one record from Gabon (Thibault 1999) and one from the Prince Edward Islands, South Africa (Kerley 1983). Australian Fur Seals are endemic to southeastern Australian waters and are found from the coasts of Tasmania, New South Wales, Victoria and across to South Australia with the centre of their distribution in Bass Strait (Kirkwood et al. 2010). The ranges of both subspecies are expanding, with the new colonies established in the last decade (Kirkman et al. 2007, Kirkwood et al. 2010, Shaughnessy et al. 2010, Kirkman et al. 2013, McIntosh et al. 2014, Shaughnessy et al. 2014). While both subspecies seldom move beyond the continental shelves, Cape Fur Seals have been recorded up to 220 km offshore (Shaughnessy 1979).
Native:Angola; Australia (New South Wales, South Australia, Tasmania, Victoria); Namibia; South Africa (Eastern Cape Province, Marion-Prince Edward Is. - Vagrant, Western Cape)
|FAO Marine Fishing Areas:|
Atlantic – southeast; Indian Ocean – eastern; Indian Ocean – western; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
Estimates indicate that approximately two million Cape Fur Seals bred at some 40 colonies or colony groups in 2009. However, there have been substantial changes in distribution during this time period with an increase in the number of colonies, a northward shift in range and an increase in abundance in some areas (northern Namibia and northwestern South Africa; Kirkman et al. 2013). In 2004 some 75% of Cape Fur Seals bred at three sites: the Atlas Bay-Wolf Bay-Long Islands Complex and Cape Cross in Namibia, and Kleinzee in South Africa (Kirkman et al. 2007). All of these sites have experienced small declines in abundance since that time (Kirkman et al. 2013). Most of the smaller rookeries are estimated to contain more than 1,000 adults. While the abundances of the larger rookeries are relatively stable, they do experience fluctuations. Fluctuations are greater in southern Namibian rookeries (Kirkman et al. 2013) which have experienced major mortality events due to the impact of poor environmental conditions on prey populations (Gammelsrød et al. 1998, Gerber and Hilborn 2001). Smaller rookeries tend to experience greater fluctuations than larger rookeries (Kirkman et al. 2007, 2013).
While rookeries of Cape Fur Seals are separated by between a few to several hundred kilometres, tag data (Oosthuizen 1991) and genetic evidence (Matthee et al. 2006) indicate substantial movement between them and no distinct subpopulations.
|Current Population Trend:||Increasing|
|Habitat and Ecology:|
Afro-Australian Fur Seals are the largest of all Fur Seals. Mean asymptotic mass and length of males is 229 kg (range 218-360 kg) and 221 cm (range 201-227 cm), and females are 85 kg (range 41-113 kg) and 163 cm (136-171 cm; Arnould and Warneke 2002, Kirkwood and Goldsworthy 2013). Pups at birth are 60-80 cm in length and weigh 5-12 kg. The Cape Fur Seal is slightly smaller (Warneke 1995).
While Cape Fur Seals forage in both pelagic and benthic environments (Kooyman and Gentry 1986, David 1987b, Stewardson 2001), Australian Fur Seals are primarily benthic feeders (Arnould and Kirkwood 2008, Kirkwood and Arnould 2011, Kirkwood and Goldsworthy 2013). Characteristics of dives vary between sites (Kooyman and Gentry 1986, Stewardson 2001, Arnould and Kirkwood 2008, Kirkwood and Arnould 2011). The majority of recorded dives of Cape Fur Seals on the west coast of South Africa are to less than 50 m depth (Kooyman and Gentry 1986), while those on the southeast coast are to more than 60 m (Stewardson 2001). Mean dive duration of Cape Fur Seals varies between one minute (Stewardson 2001) and 2.1 minutes (Kooyman and Gentry 1986). Foraging dives by lactating Australian Fur Seal females are usually to 65–85 m with a maximum depth of 164 m, and dives usually last from 2.0-3.7 minutes, with a maximum duration of 8.9 minutes (Arnould and Hindell 2001). The diurnal frequency of Cape Fur Seal dives shows a bimodal distribution with most dives taking place at dusk or during the first half of the night, with a smaller peak after dawn (Kooyman and Gentry 1986, Stewardson 2001). The maximum recorded diving depth is 204 m (Kooyman and Gentry 1986).
Cape Fur Seals are generalist foragers that take a wide variety of prey, including Cape Hake, Horse Mackerel, Pelagic Goby, Pilchards, Anchovy, squid of the genus Loligo, Rock Lobster, shrimp, prawns and amphipods (David 1987b, de Bruyn et al. 2003, Mecenero et al. 2006). They have also been reported to occasionally take African Penguins and several species of flying seabirds (Makhado et al. 2006). Australian Fur Seals eat a wide range of fish species including Redbait, Leatherjacket species, Jack Mackerel, Barracouta, Red Rock Cod and Flathead (Goldsworthy et al. 2003, Hume et al. 2004, Page et al. 2005, Littnan et al. 2007, Kirkwood et al. 2008, Deagle et al. 2009). Cephalopods are also important prey with key species being Gould’s Squid, Octopus spp., and Cuttlefish (Hume et al. 2004, Page et al. 2005, Kirkwood et al. 2008).
Great White Sharks (Pemberton and Kirkwood 1994, Martin et al. 2005) and Killer Whales (Rice and Saayman 1987) are predators of Afro-Australian Fur Seals at sea. On shore, Cape Fur Seal pups are preyed on by Black-backed Jackals and Brown Hyenas (Skinner et al. 1995, Oosthuizen et al. 1997, Kuhn et al. 2008).
|Continuing decline in area, extent and/or quality of habitat:||No|
|Generation Length (years):||9.1|
|Movement patterns:||Not a Migrant|
|Congregatory:||Congregatory (and dispersive)|
|Use and Trade:||
The commercial harvesting of Cape Fur Seals in South Africa ceased in 1990 (Wickens et al. 1991) and is now prohibited under terms of the Policy on the Management of Seals, Seabirds and Shorebirds (MLRA 2007).
Cape Fur Seals continue to be harvested commercially and hunted for trophies in Namibia under permits issued in terms of the Marine Resources Act of 2000 (Campbell et al. 2011). The most profitable product is thought to be male genitalia (Kirkman 2006), but others products are pelts, leather products, oil, meat, and bone meal for consumption (Campbell et al. 2011). In 2010, 43,168 pups and 4,573 adult males were harvested, while the 2011 harvest was 45,794 pups and 3,626 adult males (Japp et al. 2012).
The Australian Fur Seal is not harvested.
Cape and Australian Fur Seals were hunted heavily during the 17th, 18th and 19th centuries and populations of both were reduced to low levels (Warnecke and Shaughnessy 1985, David 1987a). Under protection, both have recovered, although the Cape subspecies to a much greater extent than the Australian subspecies, which has not returned to estimated pre-exploitation levels (Kirkman et al. 2013; Kirkwood et al. 2005). Levels of exploitation of Cape Fur Seals were not as severe as those experienced by other species of Fur Seals and genetic variation remains high (Matthee et al. 2006).
Harvests of Cape Fur Seals in South Africa were first controlled in 1893 and were suspended in 1990 (Wickens et al. 1991). Harvesting continues in Namibia at the mainland colonies of Cape Cross and the Wolf and Atlas Bays group (Japp et al. 2012). Harvest levels have remained high even in years with high levels of pup and adult natural mortality (Japp et al. 2012, Kirkman et al. 2007). This mortality has been attributed to a scarcity of fish and poor marine productivity along the coast of Namibia, which occurs at intervals (Gammelsrød et al. 1998, Gerber and Hilborn 2001). Australian Fur Seals are not harvested.
Cape Fur Seals are reported to interact with commercial fisheries, both via direct competition and operationally. A number of commercially exploited species of fish are eaten by Seals (David 1987b, Wickens et al. 1992). While the effects of these interactions are difficult to assess due to the complexities of the marine food web and the range of species that Seals prey on (David 1987b, Punt and Butterworth 1995), it is possible that changes in fishing effort and changes in the abundance and distribution of commercially harvested fish species may result in reduced prey populations (Barange et al. 1999, Roy et al. 2007, Moloney et al. 2013, Roux et al. 2013). The impact of direct mortality of Cape Fur Seals due to fisheries is not well known and the effects of current interactions have not been studied. Seals have been taken incidentally in past fishing operations and levels of take have been estimated to be low (Wickens et al. 1992, David and Wickens 2003). A number are also shot illegally during fishing operations (Wickens et al. 1992).
While climate change does not pose the same level of threat to the Afro-Australian Fur Seals as it does for many other species of pinnipeds, it remains important (Kovacs et al. 2012). Climate mediated changes in prey species (Barange et al. 1999, Roy et al. 2007, Moloney et al. 2013, Roux et al. 2013) may be responsible for changes in the distribution of rookeries of Cape Fur Seals (Kirkman et al. 2013). It is also possible that climate change was responsible for recent periods of high mortality along the Namibian coast (Gammelsrød et al. 1998, Gerber and Hilborn 2001). Pups are vulnerable to high temperatures (De Villiers and Roux 1992), and changes leading to higher ambient temperatures and fewer windy days may increase mortality (Kovacs et al. 2012). A number of pups are born on small and low lying islands (Kirkwood et al. 2010, Kirkman et al. 2013) and are susceptible to high mortality during summer storms (Hofmeyr et al. 2011). Rising sea levels and possible changes in the frequency of such storms induced by climate change will threaten such colonies with extirpation.
Entanglement in marine debris poses a potential threat to the Afro-Australian Fur Seals (Shaughnessy 1999, Lynch et al. 2011ab, Kirkwood and Goldsworthy 2013). Rates of entanglement vary by colony, but have been estimated to be between 0.12%-0.66% for the Cape Fur Seal (Shaughnessy 1980).
Like all Fur Seals, Afro-Australian Fur Seals are vulnerable to oil spills because of their dependence on their thick pelage for thermoregulation (Bonner 1978). Cape Fur Seals come in regular contact with a number of species of terrestrial carnivores, and both subspecies are at risk of exposure to viruses and other disease types that could lead to epidemics (Lavigne and Schmitz 1990, Kirkman 2006).
Both subspecies are visited by tourists at a number of colonies. Disturbance is believed to be minimal (Kirkwood et al. 2003).
Australian Fur Seals are protected nationally by the Environment Protection and Biodiversity Conservation Act (1999). They are also protected in all Australian states in which they occur by state-specific legislation (National Seal Strategy Group and Stewardson 2007).
Although Cape Fur Seals have been protected in South Africa since 1893 by the Fish Protection Act, and in Namibia since 1922 by the Sealing and Fisheries Proclamation, they were still subject to government run or government authorized commercial harvests (Wickens et al. 1991, Butterworth et al. 1995, David and Wickens 2003). Harvests ceased in South Africa in 1990 (Wickens et al. 1991) but continue in Namibia (Japp et al. 2012). In South Africa the Sea Birds and Seals Protection Act of 1973, provides broad protection for Seals. Furthermore, the commercial killing of Seals is now prohibited in South Africa under terms of the Policy on the Management of Seals, Seabirds and Shorebirds (MLRA 2007). While the conservation and harvesting of Seals in Namibia was previously controlled by the Sea Birds and Seals Protection Act, this has been replaced by the Marine Resources Act of 2000 which relaxed restrictions aimed at ensuring a humane harvest (Kirkman 2006, Algers et al. 2007).
|Citation:||Hofmeyr, G.J.G. 2015. Arctocephalus pusillus. The IUCN Red List of Threatened Species 2015: e.T2060A45224212.Downloaded on 24 November 2017.|
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