Arctocéphale d'Afrique du Sud

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.

The foraging distributions of both subspecies overlap extensively with commercial fishing activities, especially trawl fisheries operating in southeastern Australia (David 1987b, Wickens et al. 1992, Goldsworthy et al. 2003). Fisheries interactions therefore constitute one of the most important threats to the species, and especially for the less abundant Australian Fur Seal (v, National Seal Strategy Group and Stewardson 2007). This subspecies is subject to significant and ongoing bycatch mortality associated with demersal and mid-water trawling operations, and they constitute a significant bycatch in the mid-water trawl sector of the small pelagic fishery (Knuckey et al. 2002, Hamer and Goldsworthy 2006, Tilzey et al. 2006,  Lyle and Willcox 2008, Tuck et al. 2013). Ecological interactions with fisheries also pose a potential threat, given their reliance on small pelagics (Goldsworthy et al. 2003, Deagleet al. 2009). Australian Fur Seals also interact regularly with finfish (Salmon) aquaculture farms in Tasmania (Pemberton and Shaughnessy 1993, Hume et al. 2002, National Seal Strategy Group and Stewardson 2007, Robinson et al. 2008). At aquaculture farms, Seals are at risk of becoming entangled in nets and having their behaviour changed by becoming habituated to a predictable food source (National Seal Strategy Group and Stewardson 2007).

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).