Arctocephalus forsteri (Lesson, 1828)
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publication ID |
https://doi.org/ 10.5281/zenodo.6604474 |
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DOI |
https://doi.org/10.5281/zenodo.6604508 |
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persistent identifier |
https://treatment.plazi.org/id/965C87FE-1E5A-5649-9C19-9364876AFBF6 |
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treatment provided by |
Diego |
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scientific name |
Arctocephalus forsteri |
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New Zealand Fur Seal
Arctocephalus forsteri View in CoL
French: Otarie de Forster / German: Neuseeland-Seebar / Spanish: Lobo marino de Nueva Zelanda
Other common names: Antipodean Fur Seal, Australasian Fur Seal, Black Fur Seal, South Australian Fur Seal
Taxonomy. Otaria forsteri Lesson, 1828 ,
no type locality given. Restricted by V. B. Scheffer in 1958 to “Dusky Sound, New Zealand.”
The Australian population of A. forster: was previously referred to as A. doriferus. In a recent review, A. Berta and M. Chrurchill concluded that A. forsteri was a subspecies of A. australis , but this opinion has not gained wide use or acceptance, and the traditional view that A. forsteri is a separate speciesis followed here. Monotypic.
Distribution. New Zealand (North & South Is and on all subantarctic Is), W & S Australia and Tasmania. View Figure
Descriptive notes. Total length up to 190 cm (males) and 150 cm (females); weight 120-160 kg, maybe to 200 kg (males) and 30-50 kg (females). Newborns are 40— 55 cm and 3.3-5 kg. Dental formula 13/2, C 1/1, PC 6/5 (x 2) = 36. New Zealand Fur Seals are sexually dimorphic. Mature males are 1-3 times longer and c.3 times heavier than full-grown females. Muzzle is straight, of medium length and tapers to fleshy nose (rhinarium) that is pointed and slightly upturned. Pale vibrissae are of medium length, and ear pinnae are long and conspicuous. Long coarse guard hairs on males form mane that reaches from head to thick neck, chest, and shoulders. Males also develop small sagittal crest, which produces a slight forehead, although crown remains fairly round. Adult females, subadults, and juveniles have more flat heads without forehead rises. Flippers have dark, sparse, short fur that extends beyond wrists and ankles onto dorsal surface of flippers that are otherwise covered in black leathery skin. Foreflippers appear somewhat triangular due to straight leading edge. Muzzle has pale fur where vibrissae originate and around mouth. Males tend to have darker pelage on undersides than females. Young have a mostly black coat, with pale muzzle and abdomen that molts to an adult pelage by 2-3 months of age. Hybrid New Zealand Fur Seals x Antarctic Fur Seals and New Zealand Fur Seals x Subantarctic Fur Seals display pelage and morphology with intermediate characteristics.
Habitat. Continental shelf and slope waters, and over the Campbell Plateau, which lies south of New Zealand. Favored terrestrial habitats of New Zealand Fur Seals are rocky areas on islands that may have some shade; at times they seek bushy habitat adjacent to the shore. Predators include sharks, Killer Whales (Orcinus orca), male New Zealand Sea Lions ( Phocarctos hookeri ), and Leopard Seals (Hydrurga leptonyx) at subantarctic islands.
Food and Feeding. Diets of New Zealand Fur Seals vary depending on season and foraging area. Lactating females are known to feed nocturnally. Prey includes vertically migrating species and mid-water and bottom-dwelling species. In New Zealand, they take arrow squid (Nototodarus gouldi), barracouta (Thyrsites atun), anchovy ( Engraulidae ), lanternfish ( Myctophidae ), jack mackerel (7Trachurus sp.), red codling (Pseudophycis bachus), hoki (Macruronus novaezelandiae), octopus, and birds, including penguins and shearwaters. In South Australia, they prey on arrow squid, Gould's squid (N. gouldi), red bait (Emmelichthys nitidus), ocean jackets (Nelusetta ayraud), swallowtail (Centroberyx lineatus), and lanternfish, along with penguins and shearwaters.
Breeding. The New Zealand Fur Seal has the same general polygynous breeding system as described for the Northern Fur Seal ( Callorhinus ursinus ). For New Zealand Fur Seals, breeding occurs from mid-November to January. Territories usually contain 5-8 females that enter estrus 7-8 days after giving birth. They remain with their neonates for 1-2 days before leaving on their first foraging trip. Subsequent nursing bouts ashore usually last less than two days. Young are weaned at ¢.10 months. Hybridization is reported from Macquarie Island, where male New Zealand Fur Seals cross with female Antarctic Fur Seals and Subantarctic Fur Seals.
Activity patterns. Most of what is known about activities of New Zealand Fur Seals comes from their time spent ashore during the breeding season. At sea, they may travel or raft together in groups and groom, rest, and feed as described for the Antarctic Fur Seal. Groups frequently gather in the water just offshore of the rookery. When swimming rapidly, they may “porpoise,” or leap clear of the surface. New Zealand Fur Seals may forage in fairly shallow water, at depths to 20 m, but studies in South Australia reported adult females diving to 60-80 m on the continental shelf. Adult males were reported to dive to 100-200 m on the continental slope. Maximum depths were 312 m and up to 9-3 minutes long for females and 380 m and up to 14-8 minutes for males.
Movements, Home range and Social organization. New Zealand Fur Seals are non-migratory. In South Australia, satellite tags revealed that individuals use different foraging areas, depending on their age class and gender. Lactating females feed in midto outer-continental shelf waters in summer and then shift to deeper pelagic waters in winter. Mature male New Zealand Fur Seals tend to feed in continental slope waters. Juveniles feed in the pelagic zone. Vagrants have been recorded as far away as New Caledonia, and a bone found at an archaeological dig might be evidence of at least one individual reaching the Cook Islands.
Status and Conservation. CITES Appendix II. Classified as Least Concern on The IUCN Red List. New Zealand Fur Seals occur on the South Island, North Island (where they are less common), and all subantarctic islands of New Zealand. They occur primarily on the southern (Kangaroo Island) and western sides of Australia; small numbers are also found in Tasmania and Victoria. Total population of the New Zealand Fur Seal is ¢.200,000 individuals, split roughly equally between New Zealand and Australia, and itis increasing. Early Polynesians who immigrated to New Zealand first hunted the New Zealand Fur Seal, which might have caused initial population declines on the North Island. European sealers brought the New Zealand Fur Seal close to extinction in the 19" century, but much of its former distribution is now reoccupied because of legal protection. Fisheries are potential source of gear entanglements, and because all species of fur seals rely on their thick fur for thermoregulation, they are particularly at risk from oil spills. They may be vulnerable to diseases, such as morbilliviruses, transmitted by terrestrial wild and domestic animals. New Zealand Fur Seals have been killed by motor vehicles on roads near Kaikoura on the South Island.
Bibliography. Arnould (2009), Baker et al. (2010), Baylis, Page, McKenzie & Goldsworthy (2012), Baylis, Page, Peters et al. (2005), Berry et al. (2012), Berta & Churchill (2012), Bonner (1981), Boren et al. (2008), Brothers & Pemberton (1990), Dickie & Dawson (2003), Goldsworthy (2006), Goldsworthy & Gales (2008a), Goldsworthy & Shaughnessy (1994), Goldsworthy et al. (2009), Haase (2007), Jefferson et al. (2008), Lancaster, Gemmell et al. (2006), Lancaster, Goldsworthy & Sunnucks (2010), Ling (1987), McKenzie, Page et al. (2007), McKenzie, Parry et al. (2005), Page, McKenzie & Goldsworthy (2005), Page, McKenzie, Hindell & Goldsworthy (2005), Page, McKenzie, Mcintosh et al. (2004), Page, McKenzie, Sumner et al. (2006), Reeves & Mead (1999), Reijnders et al. (1993), Rice (1998), Scheffer (1958), Shaughnessy (2006), Shaughnessy & Gales (1990).
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