|Scientific Name:||Arctocephalus forsteri|
|Species Authority:||(Lesson, 1828)|
|Taxonomic Notes:||This species was formerly referred to Arctocephalus doriferus in Australia. Small genetic differences, but no morphological differences, between the Australian and New Zealand populations have been reported (Lento et al. 1994, Rice 1998).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Goldsworthy, S. & Gales, N. (IUCN SSC Pinniped Specialist Group)|
|Reviewer/s:||Kovacs, K. & Lowry, L. (Pinniped Red List Authority)|
Due to its large and apparently increasing population size, the New Zealand Fur Seal should be classified as Least Concern.
IUCN Evaluation of the New Zealand Fur Seal, Arctocephalus forsteri
Prepared by the Pinniped Specialist Group
A. Population reduction Declines measured over the longer of 10 years or 3 generations
A1 CR > 90%; EN > 70%; VU > 50%
Al. Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction are clearly reversible AND understood AND have ceased, based on and specifying any of the following:
(a) direct observation
(b) an index of abundance appropriate to the taxon
(c) a decline in area of occupancy (AOO), extent of occurrence (EOO) and/or habitat quality
(d) actual or potential levels of exploitation
(e) effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.
New Zealand Fur Seal abundance in New Zealand and Australia combined is approximately 200,000 individuals. The population trend is increasing. Most of the population in Australia is in South Australia, where pup production has been increasing by >12% per year on Kangaroo Island over a 20 year period. Generation time has been estimated as 9.9 years. Because the population is large and increasing, these criteria do not apply for this species.
A2, A3 & A4 CR > 80%; EN > 50%; VU > 30%
A2. Population reduction observed, estimated, inferred, or suspected in the past where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
Commercial harvesting has ceased and populations have been increasing for at least the last 30 years. Therefore, these criteria do not apply for the species.
A3. Population reduction projected or suspected to be met in the future (up to a maximum of 100 years) based on (b) to (e) under A1.
A population reduction of New Zealand fur seals is not expected in the future. However, local impacts from fisheries by-catch in parts of the range, and/or global climate change may have detrimental impacts on the species.
A4. An observed, estimated, inferred, projected or suspected population reduction (up to a maximum of 100 years) where the time period must include both the past and the future, and where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
The New Zealand Fur Seal population is still recovering from 18th, 19th and early 20th century sealing. Populations have been recovering over at least the last 30 years and are expected to continue to recover into the near future. Therefore, these criteria do not apply for the species.
B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy)
B1. Extent of occurrence (EOO): CR < 100 km²; EN < 5,000 km²; VU < 20,000 km²
The EOO is > 20,000 km².
B2. Area of occupancy (AOO): CR < 10 km²; EN < 500 km²; VU < 2,000 km²
The AOO is > 2,000 km².
AND at least 2 of the following:
(a) Severely fragmented, OR number of locations: CR = 1; EN < 5; VU < 10
(b) Continuing decline in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) area, extent and/or quality of habitat; (iv) number of locations or subpopulations; (v) number of mature individuals.
(c) Extreme fluctuations in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or subpopulations; (iv) number of mature individuals.
None of the B criteria apply for this species.
C. Small population size and decline
Number of mature individuals: CR < 250; EN < 2,500; VU < 10,000
Number of mature individuals is >10,000. These criteria do not apply for the species.
AND either C1 or C2:
C1. An estimated continuing decline of at least: CR = 25% in 3 years or 1 generation; EN = 20% in 5 years or 2 generations; VU = 10% in 10 years or 3 generations (up to a max. of 100 years in future)
C2. A continuing decline AND (a) and/or (b):
(a i) Number of mature individuals in each subpopulation: CR < 50; EN < 250; VU < 1,000
(a ii) % individuals in one subpopulation: CR = 90–100%; EN = 95–100%; VU = 100%
(b) Extreme fluctuations in the number of mature individuals.
None of the C criteria apply for this species.
D. Very small or restricted population
Number of mature individuals: CR < 50; EN < 250; VU < 1,000 AND/OR restricted area of occupancy typically: AOO < 20 km² or number of locations < 5
Number of mature individuals is >10,000. The AOO is > 2,000 km². Therefore, these criteria do not apply for the species.
E. Quantitative analysis
Indicating the probability of extinction in the wild to be: CR > 50% in 10 years or 3 generations (100 years max.); EN > 20% in 20 years or 5 generations (100 years max.); VU > 10% in 100 years
A PVA has been undertaken on the South Australian subpopulation, which suggested very low extinction probabilities. Therefore, these criteria do not apply for the species.
Listing recommendation — Populations of the New Zealand Fur Seal are presently increasing, and there is no evidence for sustained declines in any parts of their range. The breeding range of the species is still expanding in both New Zealand and Australia. Although the species is subject to by-catch in commercial fisheries in both New Zealand and Australia, these levels, at present do not appear to be inhibiting broad scale population recovery. The species should be categorized as Least Concern.
|Range Description:||In New Zealand, this species occurs around both the North and South Islands, with small breeding colonies on the north and larger colonies on the west and southern coast and islands around the South Island, as well as on all of New Zealand's sub-Antarctic islands. They are less common off the North Island, with no colonies, but they do occur as far north as the Three Kings Islands. Their range extends to Macquarie Island, where males mate with Antarctic and Subantarctic fur seals and produced hybrid pups. Vagrants have been recorded in New Caledonia and from a bone in a 14th century archaeological site in the Cook Islands.
New Zealand Fur Seals also occur in the coastal waters and on the offshore islands of South and Western Australia, from just east of Kangaroo Island west to the southwest corner of the continent in Western Australia. Small populations are also establishing in Tasmania and Victorian coastal waters.
Native:Australia; New Zealand
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The total population is estimated to be approximately 200,000 with about half of these in Australia. Populations are increasing in both Australia and New Zealand (e.g. Brothers and Pemberton 1990).|
|Habitat and Ecology:||
New Zealand Fur Seals are sexually dimorphic, with adult males reaching 1.3 times the length and more than 3 times the weight of adult females. There is some variation in the weights of adult males in the literature. Some ranges are up to a maximum of 250 kg, others to 200 kg. The largest male weighed at the Open Bay Islands of New Zealand was 154 kg. Adult males 8-12 years old had a maximum weight of 124 kg. Adult males are up to 2 m long. Adult females are 1.5 m and 30-50 kg. Pups average 3.3-3.9 kg and 40-55 cm at birth and male pups average 14.1 kg and females 12.6 kg around weaning when they are approximately 290 days old. Pups moult into adult pelage at 2-3 months. Females become mature at 4-6 years of age, males at 8-10 years (Dickie and Dawson 2003, McKenzie et al. 2005, 2007).
New Zealand Fur Seals are polygynous. Males arrive at colonies in late October before females and acquire and defend territories with vocalizations, ritualized displays and fighting. Male territories include an average of 5-8 females with the ratio of females to males varying between different colonies. The number of animals ashore at rookeries declines rapidly in January. Male vocalizations include a bark or whimper, a guttural threat, a low-intensity threat, a full threat, and a submissive call. Females growl and have a pup-attraction call that is a high-pitched wail.
Pups are born from mid-November to January, with most pups are born in December. Oestrous occurs 7-8 days after a female gives birth, and they usually spend another 1-2 days ashore with their pup before departing and beginning a cycle of foraging trips and periods of pup attendance ashore (Goldsworthy and Shaughnessy 1994, Goldsworthy 2006). Pups are weaned when they are about 10 months old. Adult female foraging trips are shorter when the pup is young and become longer as the pup gets older. In general, on-shore attendance bouts last under 2 days.
New Zealand Fur Seals are considered non-migratory. At sea they actively groom and raft in a variety of postures typical of southern fur seals including the “jug handle” position while sleeping at the surface. They often “porpoise” out of the water when travelling rapidly at sea. Rocky shoreline habitat with shelter, and locations more exposed to wind and weather are preferred for haul-outs and rookeries. When hauled out in New Zealand, New Zealand fur seals readily enter areas of coastal vegetation behind the shoreline.
New Zealand Fur Seals prey on a large variety of cephalopods, fish, and birds (Goldsworthy et al. 2003). In South Australia, key cephalopods prey include, Southern Ocean arrow squid and Gould’s squid; key fish species include redbait, ocean jackets, swallowtail and myctophids; and the most frequently taken bird species are little penguins and short-tailed shearwaters. Satellite tracking studies in South Australia indicate marked spatial separation in foraging regions used by juvenile, adult female and males seals. Lactating females forage predominantly in mid- to outer-continental shelf waters during summer months and then switch to deeper oceanic waters over winter months. In contrast, adult males focus their foraging over the continental slope. Juvenile seals forage in oceanic waters where they target nocturnal surface-migrating myctophid fish (Baylis et al. 2005). Adult female and male seals both forage in the water column in relative shallow depths (0-20 m) and near or on the bottom in deeper water. In females, benthic dives on the continental shelf in South Australia are typically at 60-80 m, while those of males on the continental slope are between 100-200 m. The maximum dive durations and depths recorded for adult females are 9.3 min and 312 m, and 14.8 min and 380 m for males.
Predators include Killer Whales, sharks, male New Zealand Sea Lions and possibly Leopard Seals at sub-Antarctic islands (Shaughnessy 2006).
Humans have probably harvested New Zealand Fur Seals for subsistence since first contact in both Australia and New Zealand. There is evidence that Polynesian colonization of New Zealand and harvest of seals led to declines and loss of colonies on the coast of the North Island. European sealers nearly exterminated the species in the 19th century, but due to protection, the species has rebounded to occupy most of its former range.
Trawl and other fisheries are a source of entanglement and drowning (Page et al. 2004). Tourism and disturbance at colonies can lead to disruption of breeding behaviour and site abandonment, although most colonies are on offshore islands and are relatively inaccessible.
Like all fur seals, New Zealand Fur Seals are vulnerable to oil spills because of their dependence on their thick pelage for thermoregulation (Gales 1991). New Zealand fur seals share most of their range with several other regularly occurring pinnipeds that show up irregularly as vagrants. They also come in close contact with domestic and feral animals and in some areas wild carnivores. Thus, they are at risk of transmission of infectious diseases like morbilliviruses.
This species is protected throughout its range by the laws of Australia and New Zealand, respectively. In New Zealand all marine mammals are protected by the Marine Mammals Protection Act of 1978. Management is driven by Conservation Plans developed by the Department of Conservation. The current plan, written in 2004, is an action plan for conservation of all marine mammals from 2005-2010 (Suisted and Neale 2004). In Australia, State Governments have jurisdiction over marine mammals within three miles of the coast and each state has its own conservation legislation. The Australian Commonwealth Government has jurisdiction from three miles offshore throughout the rest of the countries’ 200 mile EEZ. An action plan for conservation of Australian seals was published in 1999 (Shaughnessy 1999).
It is listed on CITES Appendix II.
|Citation:||Goldsworthy, S. & Gales, N. (IUCN SSC Pinniped Specialist Group) 2008. Arctocephalus forsteri. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 22 May 2013.|
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