''Arctocephalus forsteri'' (
common names include the Australasian fur seal,
South Australian fur seal,
New Zealand fur seal,
Antipodean fur seal, or long-nosed fur seal) is a species of
fur seal
Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family '' Otariidae''. They are much more closely related to sea lions than true seals, and share with them external ears (pinnae), relatively l ...
found mainly around southern
Australia and
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
.
The name ''New Zealand fur seal'' is used by English speakers in New Zealand; ''kekeno'' is used in the
Māori language.
[ , the common name long-nosed fur seal has been proposed for the population of seals inhabiting Australia.]
Although the Australian and New Zealand populations show some genetic differences, their morphologies are very similar, and thus they remain classed as a single species. After the arrival of humans in New Zealand, and particularly after the arrival of Europeans in Australia and New Zealand, hunting
Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products ( fur/ hide, bone/tusks, horn/antler, ...
reduced the population to near-extinction.
Description
Males have been reported as large as 160 kg; their average weight is about 126 kg.[Harcourt, R.G., (2001)]
"Advances in New Zealand mammalogy 1990–2000: Pinnipeds"
''Journal of The Royal Society of New Zealand'', Retrieved 6 October 2011 Males can be 2 metres long. Females are between 30–50 kg on average, and can be as long as 1.5 metres. Pups are 3.3–3.9 kg on average, and between 40 and 55 cm long. At 290 days old males are about 14.1 kg, and females are about 12.6 kg. Like other otariids
An eared seal or otariid or otary is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds. They comprise 15 extant species in seven genera (another species became extinct in the 1950s) and are commonly known eit ...
, they have external ears and hind flippers that rotate forward, which visibly distinguish them from true seals
The earless seals, phocids or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae (). They are sometimes called crawling seals to distinguish them from th ...
.[Department of Conservation]
"New Zealand fur seal/kekeno"
Retrieved 6 October 2011. They have a pointy nose with long pale whiskers.[ Fur seals are covered by two layers of fur. The coat is grey-brown on their back, and lighter on their belly.][ Some have white tips on longer upper hairs, which can give them a silver-like appearance.][
So called "Upland Seals" once found on ]Antipodes Islands
The Antipodes Islands ( Maōri: Moutere Mahue; "Abandoned island") are inhospitable and uninhabited volcanic islands in subantarctic waters to the south of – and territorially part of – New Zealand. The 21 km2 archipelago lies 860  ...
and Macquarie Island
Macquarie Island is an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica. Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in 197 ...
have been claimed as a distinct subspecies with thicker furs by scientists although it is unclear whether these seals were genetically distinct.
Distribution
The species occurs in Australia and New Zealand. It is found in the coastal waters and on the offshore islands of southern Australia, from the south-west corner of Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
to just east of Kangaroo Island
Kangaroo Island, also known as Karta Pintingga (literally 'Island of the Dead' in the language of the Kaurna people), is Australia's third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia, southwest ...
in South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
, and also in southern Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
and the subantarctic Macquarie Island
Macquarie Island is an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica. Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in 197 ...
. Small populations are forming in Bass Strait and coastal waters of Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
and New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
as far as the mid-north coast. Before the arrival of humans in New Zealand, the species bred around all the New Zealand mainland and its subantarctic islands. There are now established and expanding colonies around the entire South Island, on Stewart Island and all of the New Zealand subantarctic islands. There are also newly established breeding colonies on the North Island.
Behaviour
Diving
The species can "porpoise" out of the water when travelling quickly at sea. They can dive deeper and longer than any other fur seal.[ Females can dive for about 9 minutes and to a depth of about 312 metres, and can dive deeper and longer in autumn and winter. Males can dive for about 15 minutes to a depth of about 380 metres.] On average, the species typically only dives for 1–2 minutes.[ When they dive for food they dive deeper during the day but shallower at night, because during the day their prey typically migrates to deeper depths and migrates back up during the night ( diel vertical migration).][
Lactating females alter their dive patterns in order to regularly care for their young. Dives are shorter, from around 9 minutes down to 5 minutes. Several longer trips may be taken at first to find patches of prey. The shorter dives then utilise these patches. Due to the differences in diving pattern between males and females, there is very little inter-sexual competition for food sources. Males typically forage over continental shelf breaks in deeper water, while females typically utilise the continental shelf as foraging grounds. It is believed that differences in diving abilities and depths could be the cause of some ]sexual dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...
between males and females.
Diving behaviour by the pups begins in the months leading up to weaning, when the pups are nursing less. The pups begin to dive from the age of 6–10 months, yet weaning is known to occur between the ages of 8 and 11 months, so the young pups do not have much time to learn to forage. The pups need to progressively develop nocturnal diving skills while they still have their mothers' milk to fall back on if dives are unsuccessful. Age, physiological development, and experience are important factors for success in hunting and contribute to the development of the pups' diving ability and behaviour. This transitional period, when young pups are becoming nutritionally independent while their foraging efficiency is rather low, is a time of high risk, and mortality can be very high. Based on scat samples, it has been found that the pups start by eating cephalopods and eventually making their way to fish, but this may just be a result of prey availability during different times of the year.
Communication
Males vocalise through a bark or whimper, either a guttural threat, a low-intensity threat, a full threat, or a submissive call. Females growl and also have a high-pitched pup attraction wail call. Pup-attraction calls allow communication from longer distances. Once together, females use olfactory recognition to confirm the pup as their own.[Ian Stirling; Observations on the Behavior of the New Zealand Fur Seal (''Arctocephalus Forsteri''), ''Journal of Mammalogy'', Volume 51, Issue 4, 30 November 1970, Pages 766–778, ] In males, the full neck display is a non-combative posture that functions as a threat to surrounding males by which they are able to assess each other's dominance status.
Reproduction
Females mature between 4 and 6 years old, and males mature between 8 and 10 years old. These seals are polygynous.[ Males obtain and guard territory in late October before females arrive.] Often females mate only once a year, and this usually occurs eight days postpartum for about 13 minutes on average. Females have a delayed implantation of the fertilised egg, so that implantation on the uterine wall does not occur for 3 months.[ Gestation occurs for 9 months][ Females are more aggressive near the time of birth, and do not like to be approached right after birth.][ Females will continue to reproduce until their death which is on average between 14 and 17 years of age.][
Females first arrive on the shore between November and January,] just a few days before giving birth, and stay close to the birth site for up to ten days. When they are close to labour they become very restless and irritable. When beginning labour
Labour or labor may refer to:
* Childbirth, the delivery of a baby
* Labour (human activity), or work
** Manual labour, physical work
** Wage labour, a socioeconomic relationship between a worker and an employer
** Organized labour and the labour ...
, which can last as much as five hours, they lie down and toss their head in the air, straining forward on their fore flippers, lifting their hind quarters, or moving laterally, before slowly lowering their head down, a process they repeat until they finally give birth. In one study, observations of the actual birth, starting from when the pup was first seen, found an average of 2 minutes for a head-first delivery, but an average of 6.5 minutes if the pup came out tail first. Immediately after birth the mother begins frequently sniffing the newborn pup to better identify when she has to find it after a trip out to sea. Pups are fairly mature at birth, and within 60 minutes they start suckling for about 7 minutes. Eventually the suckling can exceed 33 minutes.[
The mothers may take from 45 minutes to 3 days before leaving the pups to swim, and 6–12 days to go on longer feeding trips. Even then, the mothers tend to not leave the pups for longer than 2 days. When the pups are about 21 days old they have been seen to congregate into little pods while their mothers are away. When the females return they only feed their own pups, and have been seen to be hostile toward pups that are not their own.
Female seals have been documented to have a gradual increase in trips for feeding throughout ]lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...
. It has been found that mothers who have sons made longer foraging
Foraging is searching for wild food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce. Foraging theory is a branch of behavioral ecology that studies the foraging behavi ...
trips then the mothers who had daughters during the lactation period. When observing growth patterns in the male and female pups within two cohorts, it is recognised that the growth patterns are similar, however the males grow faster and are weaned off nursing heavier in some years. Suckling can occur for about 300 days. Pups start to eat solid food just before weaning
Weaning is the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother's milk.
The process takes place only in mammals, as only mammals produce milk. The infan ...
,[ and are eventually weaned around September, when they disperse.][
Pup mortality has been attributed to both natural factors and human interaction. The biggest natural cause of death for pups is starvation, followed by suffocation in the amnion, stillbirth, trampling, drowning, and predation.] Human factors include the handling of pups, tagging, and human presence in general.
Diet
Their diet includes cephalopods, fish, and birds. In New Zealand, New Zealand octopus and arrow squid make up most of their cephalopod diet. Individuals located near their southern range limit have been known to eat penguins
Penguins (order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adapt ...
as part of their diet. Stomach contents have been analysed and shown to include Australian anchovy
The Australian anchovy, ''Engraulis australis'', is a species of anchovy of the family Engraulidae, found off south-east Australia, and around New Zealand.
The Australian anchovy feeds on plankton and is of minor importance to commercial fisher ...
, barracouta, '' Paralichthyes'' flounders, broadgilled hagfish, pouched lamprey
The pouched lamprey (''Geotria australis''), also known as the korokoro or wide-mouthed lamprey, is a species in the genus ''Geotria'', which is the only genus in the family Geotriidae. The second species in the genus is the Argentinian lamprey ...
, red cod
''Pseudophycis'' is a genus of codlings of the family Moridae found around New Zealand and Southern Australia.
Species
The currently recognized species in this genus are:
* '' Pseudophycis bachus'' ( J. R. Forster, 1801) (red codling)
* ''Pseud ...
, school shark
The school shark (''Galeorhinus galeus'') is a houndshark of the family Triakidae, and the only member of the genus ''Galeorhinus''. Common names also include tope, tope shark, snapper shark, and soupfin shark. It is found worldwide in temperate ...
, and many other species.[Boren, L. (2010]
"Diet of New Zealand fur seals (''Arctocephalus forsteri''): a summary"
Retrieved 6 October 2011 Further analysis of otoliths from their scat show that for fish prey species, lanternfishes composed the majority of their fish diet, followed by Australian anchovies, ahuru
The ahuru (''Auchenoceros punctatus'') is a species of morid cod found in waters off the eastern coast of New Zealand and to the south as well as in the Cook Strait. It is found at depths from . This species grows to in total length. It is t ...
, and hoki. There are different factors that affect their diet, such as season, sex, breeding, surrounding colony, oceanography, and climatic patterns.[
]
Predators
Known predators are killer whales
The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pat ...
, sharks, male New Zealand sea lion
The New Zealand sea lion (''Phocarctos hookeri''), once known as Hooker's sea lion, and as or (male) and (female) in Māori, is a species of sea lion that is endemic to New Zealand and primarily breeds on New Zealand's subantarctic Auckland ...
s, and possibly leopard seal
The leopard seal (''Hydrurga leptonyx''), also referred to as the sea leopard, is the second largest species of seal in the Antarctic (after the southern elephant seal). Its only natural predator is the orca. It feeds on a wide range of prey incl ...
s. New Zealand sea lions are also known to target pups as their prey.[Bradshaw, C.J.A., Lalas, C., & McConkey, S. (1998)]
"New Zealand sea lion predation on New Zealand fur seals"
''New Zealand Journal of Marine and Freshwater Research''. Retrieved 6 October 2011 Several regurgitations by sea lions have been found to contain remains of fur seal pups, some with plastic tags previously attached to female fur seal pups.
Human impact
Before the arrival of humans, the seals bred around all of New Zealand. Hunting by the first New Zealand settlers, the Maori, reduced their range. Commercial hunting
Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products ( fur/ hide, bone/tusks, horn/antler, ...
from shortly after the European discovery of New Zealand in the 18th century until the late 19th century reduced the population near to extinction.
Today, commercial fisheries are one of the main causes of death in New Zealand fur seals, usually by entanglement and drowning. Monitoring of these pinnipeds in the Kaikoura region found that entanglements with green trawl nets and plastic strapping tape were the most common. A little less than half of the individuals were successfully released with good chances of survival even after significant entanglement wounds. It has been estimated by the Royal Forest and Bird Protection Society
Forest & Bird ( mi, Te Reo o te Taiao), also known by its formal name as the Royal Forest and Bird Protection Society of New Zealand, is an environmental organisation specialising in the protection and conservation of New Zealand's indigenous f ...
that over 10,000 seals could have drowned in nets between 1989 and 1998.[ They are also known to have been shot by commercial and recreational fishermen, because they are assumed to interfere with fishing gear. How often these shootings occur is unknown, but pressure groups have stated that the conflict between the seals and commercial fisheries is expected to increase.][MarineBio.org (2011)]
"New Zealand Fur Seals, ''Arctocephalus forsteri'' at MarineBio.org"
Retrieved 6 October 2011. On 21 August 2014, two decomposing animals were found beheaded near Louth Bay
Louth Bay (formerly Laurence) is a town and locality in the Australian state of South Australia. It is named after the bay named by Matthew Flinders on 26 February 1802 which itself is derived from a place in Lincolnshire. At the 2006 census, L ...
in South Australia. The circumstances of their deaths were considered suspicious and an investigation followed their discovery. In 2015, several conservative members of Parliament encouraged public debate around the potential implementation of seal culling in South Australia in response to increasing interactions with South Australian commercial fisheries. , the killing of long-nosed fur seals remains an illegal act.
Human activity near seal rookeries has been correlated with distress and panic, resulting in indirect deaths of pups. The use of metal cattle ear tags on pups has also been associated with a decrease in pup fitness due to incomplete healing of the tag site.
Legislative protection
Australia
In Australian Commonwealth waters, ''Arctocephalus forsteri'' is protected under the '' Environment Protection Biodiversity Conservation (EPBC) Act 1999,'' under which it is listed as a protected marine species. The species is also protected within the jurisdictions of the following Australian states:
The species received protection by the creation of the 16 million hectare
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...
Macquarie Island Marine Park
The Macquarie Island Marine Park (previously known as the Macquarie Island Commonwealth Marine Reserve) is an Australian marine parks, Australian marine park near Macquarie Island in the southwest Pacific Ocean, Pacific. The marine park covers ...
, located on the eastern side of Macquarie island
Macquarie Island is an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica. Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in 197 ...
. In 2000, the Tasmanian government extended the Macquarie Island Nature Reserve by 3 nautical miles surrounding the island.
New Zealand
In New Zealand, the species is protected by the ''Marine Mammals Protection Act 1978
The Marine Mammals Protection Act 1978 is an Act of Parliament passed in New Zealand in 1978. It is administered by the Department of Conservation.
The environmental organisation Project Jonah gave the major impetus for the government to crea ...
'', which works to conserve marine animal species; it specifies that all wild pinniped
Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammal, marine mammals. They comprise the extant taxon, extant family (biology ...
s cannot be touched or fed.
Gallery
File:Arctocephalus forsteri LC0255.jpg, South Island, New Zealand
Image:Squinting seal.jpeg, coming ashore below Taiaroa Head
Taiaroa Head is a headland at the end of the Otago Peninsula in New Zealand, overlooking the mouth of the Otago Harbour. It lies within the city limits of Dunedin. The nearest settlement, Otakou, lies three kilometres to the south.
The cape is h ...
, near Dunedin
Dunedin ( ; mi, Ōtepoti) is the second-largest city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from , the Scottish Gaelic name for Edinburgh, the capital of Scotland. Th ...
, New Zealand
Image:Seal Cubs-Palliser Bay-20070331.jpg, pups at Palliser Bay
Palliser Bay is at the southern end of the North Island of New Zealand, to the southeast of Wellington. It runs for 40 kilometres along the Cook Strait coast from Turakirae Head at the southern end of the Remutaka Ranges to Cape Palliser, the Nor ...
, New Zealand
Image:Castlepoint Fur Seal.jpg, at Castlepoint, New Zealand
See also
* Seal culling in South Australia
* Sealers' War
The Sealers' War (1810–1821) in southern New Zealand (then part of the Colony of New South Wales), also known as the "War of the Shirt", was a series of often indiscriminate attacks and reprisals between Māori and European sealers. Initially ...
(1810s–1820s, New Zealand)
References
Sources
*
External links
* New Zealand fur seal discussed on RNZ ''Critter of the Week''
28 July 2017
{{Authority control
Arctocephalus
Pinnipeds of New Zealand
Mammals of Tasmania
Mammals of Western Australia
Mammals of South Australia
Mammals of New South Wales
Mammals of Victoria (Australia)
Mammals described in 1828
Taxa named by René Lesson
Fauna of subantarctic islands
Fauna of the Campbell Islands
Pinnipeds of Australia