Seasonal oscillation in shore attendance and transience of New Zealand fur seals

1999 ◽  
Vol 77 (5) ◽  
pp. 814-823 ◽  
Author(s):  
Corey JA Bradshaw ◽  
Chris Lalas ◽  
Lyndon Perriman ◽  
Robert G Harcourt ◽  
Hugh Best ◽  
...  
Keyword(s):  
New Zealand ◽  
Population Size ◽  
Relative Abundance ◽  
Fur Seals ◽  
Large Numbers ◽  
Fur Seal ◽  
Seasonal Oscillation ◽  
Estimate Population Size ◽  
New Zealand Fur Seal ◽  
Seasonal Oscillations

The New Zealand fur seal (Arctocephalus forsteri) appears to show regular shore attendance in the form of seasonal oscillations. This phenomenon should be quantified to properly interpret counts of fur seals >1 year old (i.e., non-pups). Here we test the predictability of peaks in the annual shore-attendance oscillation on Otago Peninsula using an autoregressive sine model and >2 years of intensive survey data. We predicted that the peak in fur seal numbers ashore would lie between 14 January - 4 April (1996) and 8 January - 2 April (1997), although this low predictability is undesirable when attempts are made to monitor population trends. Estimating population size from counts of non-pups also requires knowledge of the rate of turnover of individuals. Therefore, we tested the hypothesis that tagged animals from other colonies are immigrants to Otago Peninsula. With sightings on Otago Peninsula of fur seals tagged elsewhere in New Zealand, we used a Monte Carlo approach to simulate the expected frequency of single and multiple sightings of individuals. We found that the observed frequency of multiple sightings was significantly less than predicted by the model (P < 0.0001), indicating that tagged animals were transients. We also discovered that the sex ratio of tagged animals varied with breeding colony of origin (G1 = 52.07, P < 0.0001), suggesting that the impetus for emigration differs among colonies. We concur with the view that counting pups is the only way to estimate the relative abundance of New Zealand fur seals. In addition, we showed that counts of non-pups cannot be used to estimate population size because an unknown proportion of individuals is transient. However, counting of pups does not address the issue of estimating relative abundance for locations with large numbers of nonbreeding individuals and few or no breeders. With few or no pups it is impossible to estimate relative abundance using counts of pups.

First contemporary record of New Zealand fur seals Arctocephalus forsteri breeding in Bass Strait.

2000 ◽  
Vol 22 (1) ◽  
pp. 57 ◽  
Author(s):  
JPY Arnould ◽  
CL Littnan ◽  
GM Lento
Keyword(s):  
New Zealand ◽  
Southeastern Australia ◽  
Fur Seals ◽  
Large Numbers ◽  
Fur Seal ◽  
Late Eighteenth ◽  
Statutory Protection ◽  
New Zealand Fur Seal

DURING the late eighteenth and early nineteenth centuries (1798 - 1825), large numbers of fur seals were hunted on the islands off southeastern Australia. It is estimated that >300,000 pelts were collected before hunting became commercially nonviable and the seals gained statutory protection in 1889 (Warneke and Shaughnessy 1985). Two types of fur seals were known to occur in southeastern Australian waters but cargo records from the sealing vessels active in the area do not accurately identify the species taken, referring to them only as ?black? and ?brown? seals (Goldsworthy et al. 1997). There are currently two species of fur seal found in these waters: the New Zealand fur seal (Arctocephalus forsteri) and the Australian fur seal (Arctocephalus pusillus doriferus). Based on pelage colour, it has been suggested that these species correspond to the ?black? and ?brown? species, respectively, referred to by the sealers (Goldsworthy et al. 1997).

Records of vagrant fur seals (family Otariidae) in South Australia

2014 ◽  
Vol 36 (2) ◽  
pp. 154 ◽  
Author(s):  
Peter D. Shaughnessy ◽  
Catherine M. Kemper ◽  
David Stemmer ◽  
Jane McKenzie
Keyword(s):  
New Zealand ◽  
South Australia ◽  
The South ◽  
South Indian Ocean ◽  
Fur Seals ◽  
South Indian ◽  
Fur Seal ◽  
New Zealand Fur Seal ◽  
The Antarctic ◽  
Subantarctic Fur Seals

Two fur seal species breed on the southern coast of Australia: the Australian fur seal (Arctocephalus pusillus doriferus) and the New Zealand fur seal (A. forsteri). Two other species are vagrants: the subantarctic fur seal (A. tropicalis) and the Antarctic fur seal (A. gazella). We document records of vagrant fur seals in South Australia from 1982 to 2012 based primarily on records from the South Australian Museum. There were 86 subantarctic fur seals: 49 specimens and 37 sightings. Most (77%) were recorded from July to October and 83% of all records were juveniles. All but two specimens were collected between July and November. Sightings were prevalent during the same period, but there were also nine sightings during summer (December–February), several of healthy-looking adults. Notable concentrations were near Victor Harbor, on Kangaroo Island and Eyre Peninsula. Likely sources of subantarctic fur seals seen in South Australia are Macquarie and Amsterdam Islands in the South Indian Ocean, ~2700 km south-east and 5200 km west of SA, respectively. There were two sightings of Antarctic fur seals, both of adults, on Kangaroo Island at New Zealand fur seal breeding colonies. Records of this species for continental Australia and nearby islands are infrequent.

Changes in the abundance of New Zealand fur seals, Arctocephalus forsteri, on Kangaroo Island, South Australia

1995 ◽  
Vol 22 (2) ◽  
pp. 201 ◽  
Author(s):  
PD Shaughnessy ◽  
SD Goldsworthy ◽  
JA Libke
Keyword(s):  
New Zealand ◽  
South Australia ◽  
Early Years ◽  
Mark Recapture ◽  
Fur Seals ◽  
Fur Seal ◽  
Rate Of Increase ◽  
New Zealand Fur Seal ◽  
Breeding Seasons ◽  
Made In

Kangaroo Island was an important seal-harvesting site during the early years of European colonisation of Australia. A recent survey of the New Zealand fur seal, Arctocephalus forsteri, in South and Western Australia indicates that Kangaroo I. is still an important centre for the species. In order to determine changes in the abundance of the population, numbers of pups were determined at four colonies on Kangaroo Island by mark-recapture in up to five breeding seasons from 1988-89 to 1992-93. Clipping was the preferred technique for mark-recapture estimation of pups because it was quick, easy and effective. Recaptures were conducted visually; they were repeated several times in each season to improve precision of the estimates. No pups were marked between recaptures in order to minimise disturbance. Assumptions made in estimating population size by the mark-recapture technique pertinent to this study are reviewed. Pup numbers increased at three colonies: at Cape Gantheaume, from 458 to 867 over five years (with exponential rate of increase r = 0.16, n = 5); at Nautilus North, from 182 to 376 over five years (at r = 0.19, n = 4); and at North Casuarina Islet, from 442 to 503 over four years (at r = 0.043, n = 2). Rates of increase in the first two colonies are similar to those at the most rapidly increasing fur seal populations in the Southern Hemisphere. The Kangaroo I. population is estimated to be 10000 animals in 1992-93. It is likely to be at the recolonisation phase of growth, with high rates of increase at individual colonies (or parts of colonies) resulting from local immigration. As space does not appear to be limiting expansion in these colonies, fur seal numbers may continue to increase there.

Australian fur seals establish haulout sites and a breeding colony in South Australia

2010 ◽  
Vol 58 (2) ◽  
pp. 94 ◽  
Author(s):  
Peter D. Shaughnessy ◽  
Jane McKenzie ◽  
Melanie L. Lancaster ◽  
Simon D. Goldsworthy ◽  
Terry E. Dennis
Keyword(s):  
Mitochondrial Dna ◽  
New Zealand ◽  
South Australia ◽  
Breeding Colony ◽  
Mitochondrial Dna Control Region ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Fur Seals ◽  
Fur Seal ◽  
New Zealand Fur Seal

Australian fur seals (Arctocephalus pusillus doriferus) breed on Bass Strait islands in Victoria and Tasmania. They have been recorded in South Australia (SA) for many years as non-breeding visitors and on Kangaroo Island frequently since 1988, mostly in breeding colonies of the New Zealand fur seal (A. forsteri) which is the most numerous pinniped in SA. Australian fur seals have displaced New Zealand fur seals from sections of the Cape Gantheaume colony on Kangaroo Island. North Casuarina Island produced 29 Australian fur seal pups in February 2008. Australian fur seal pups were larger than New Zealand fur seal pups in the same colony and have been identified genetically using a 263-bp fragment of the mitochondrial DNA control region. North Casuarina Island has been an important breeding colony of New Zealand fur seals, but pup numbers there decreased since 1992–93 (contrary to trends in SA for New Zealand fur seals), while numbers of Australian fur seals there have increased. This study confirms that Australian fur seals breed in SA. The two fur seal species compete for space onshore at several sites. Australian fur seals may compete for food with endangered Australian sea lions (Neophoca cinerea) because both are bottom feeders.

Trends in abundance of New Zealand fur seals, Arctocephalus forsteri, at the Neptune Islands, South Australia

2002 ◽  
Vol 29 (4) ◽  
pp. 363 ◽  
Author(s):  
P. D. Shaughnessy ◽  
A. McKeown
Keyword(s):  
New Zealand ◽  
South Australia ◽  
The South ◽  
The North ◽  
Fur Seals ◽  
Fur Seal ◽  
Seal Population ◽  
Island Group ◽  
Direct Counting ◽  
New Zealand Fur Seal

At the Neptune Islands in early February 2000 at the end of the 1999–2000 pupping season, the abundance of New Zealand fur seal pups was determined using a mark–recapture technique in large colonies and by direct counting in small ones. Pups (n = 2355) were marked by clipping hair on the head to reveal light-coloured underfur. At the North Neptune group, there were 4221 pups and at the South Neptune group 1767 pups, making a total of 5988 pups for the Neptune Island group as a whole. At the North Neptune Islands, pup numbers increased by 53% since February 1993, from 2756 to 4221. For the South Neptune group, pup numbers decreased by 6.7%, from 1893 to 1767. The decrease was spread over most colonies on the island. The large increase in pup numbers at the North Neptune group indicates that the population there is in the recolonisation phase of growth; at the South Neptune group, the fur seal population is likely to be in the maturity phase, with fluctuations in size expected in the future. The Neptune Island group supports the largest aggregation of pinnipeds in Australia.

Breeding Habitat Preferences of the New Zealand Fur Seal (Arctocephalus forsteri) on Banks Peninsula

1997 ◽  
Vol 24 (2) ◽  
pp. 225 ◽  
Author(s):  
Christine J. Ryan ◽  
G. J. Hickling ◽  
Kerry-Jayne Wilson
Keyword(s):  
New Zealand ◽  
Habitat Preferences ◽  
Breeding Habitat ◽  
Classification Rule ◽  
Linear Discriminant ◽  
Habitat Features ◽  
Fur Seals ◽  
Fur Seal ◽  
Habitat Differences ◽  
New Zealand Fur Seal

Colonies of New Zealand fur seals (Arctocephalus forsteri) on Banks Peninsula, New Zealand, were surveyed between March and August 1993 to compare breeding and non-breeding habitat features. Breeding habitat was characterised by large angular boulders, beaches that were steeper than those of non-breeding habitat, and numerous escape zones, crevices and ledges. Non-breeding habitat was less steep, had smaller rounder boulders and was less exposed to the sun. Multivariate analyses confirmed that overall habitat differences were statistically significant (P < 0·05). A linear discriminant function was calculated for the two habitat types. The resulting classification rule suggested that crevices, ledges and slope were particularly useful predictors of breeding status. The rule had 96% success in classifying the original sites as breeding or non-breeding and now requires validation by further field surveys in areas with different climate, geology and latitude. If establishment of breeding colonies at sites currently used only by non- breeding seals can be predicted from habitat features, this could provide useful information for managers of coastal sanctuaries.

Drift dives by male New Zealand fur seals (Arctocephalus forsteri)

2005 ◽  
Vol 83 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Brad Page ◽  
Jane McKenzie ◽  
Mark A Hindell ◽  
Simon D Goldsworthy
Keyword(s):  
New Zealand ◽  
South Australia ◽  
Near Surface ◽  
Negative Change ◽  
Fur Seals ◽  
Fur Seal ◽  
Direct Energy ◽  
New Zealand Fur Seal ◽  
Passive Drift ◽  
Active Locomotion

Some phocid seal diving-behaviour studies have identified dives characterised by a period of passive drifting through the water column, rather than active locomotion. During these "drift dives" seals are thought to preferentially direct energy towards processing of food, lactate, or renal metabolites rather than to active propulsion. We describe the first drift dives reported in an otariid, the New Zealand fur seal (Arctocephalus forsteri (Lesson, 1828)), studied at Kangaroo Island in South Australia. Not all males in the study undertook drift dives and those that did were significantly heavier than those that did not, suggesting that body size may influence the propensity to drift dive in New Zealand fur seals. Drift dives lasted 6.0 ± 1.78 min and had passive drift segments of 3.5 ± 1.5 min, during which seals showed a negative change in depth (i.e., sinking) of 0.14 ± 0.05 m/s. Drift dives occurred at night and were possibly undertaken to avoid near-surface predators and to process food, lactate, or renal metabolites while resting.

Instances of predation on fur seals by white sharks in South Australia.

2006 ◽  
Vol 28 (1) ◽  
pp. 107 ◽  
Author(s):  
P. D. Shaughnessy
Keyword(s):  
New Zealand ◽  
South Australia ◽  
White Shark ◽  
Carcharodon Carcharias ◽  
Fur Seals ◽  
Fur Seal ◽  
New Zealand Fur Seal

A white shark (Carcharodon carcharias) was observed chasing and catching a New Zealand fur seal (Arctocephalus forsteri) at Kangaroo Island, South Australia.

The long-nosed fur seal (Arctocephalus forsteri) in South Australia in 2013–14: abundance, status and trends

2015 ◽  
Vol 63 (2) ◽  
pp. 101 ◽  
Author(s):  
P. D. Shaughnessy ◽  
S. D. Goldsworthy ◽  
A. I. Mackay
Keyword(s):  
New Zealand ◽  
South Australia ◽  
Australian Population ◽  
North West ◽  
The North ◽  
Fur Seals ◽  
Fur Seal ◽  
Increasing Trend ◽  
Small Sites ◽  
New Zealand Fur Seal

The long-nosed (or New Zealand) fur seal (Arctocephalus forsteri) breeds in southern Australia and New Zealand. Most of the Australian population is in South Australia, between Kangaroo Island and Eyre Peninsula. Fur seal populations in southern Australia were heavily exploited by colonial sealers between 1801 and 1830, resulting in major reductions. Numbers remained low for 150 years, then slowly built up and new colonies established across their presumed former range. Here we present estimates of pup abundance at South Australia colonies, mostly during the 2013–14 breeding season. Long-nosed fur seals bred from Baudin Rocks in the south-east to Fenelon Island in the north-west. In total, 29 breeding colonies produced 20 431 pups, 3.6 times greater than the 1989–90 estimate; the increase is attributed to recovery from 19th century overharvesting. The 2013–14 pup estimate leads to an estimate of abundance of long-nosed fur seals in South Australia of 97 200. Most pups were on Kangaroo Island (49.6%) and the Neptune Islands (38.6%). New breeding colonies were identified on Williams Island and at two small sites on Kangaroo Island. The increasing trend in South Australia is likely to continue over the coming decade, primarily by expansion in colonies on Kangaroo Island and by establishment of new colonies.

Status of Australian sea lions, Neophoca cinerea, and New Zealand fur seals, Arctocephalus forsteri, on Eyre Peninsula and the far west coast of South Australia

2005 ◽  
Vol 32 (1) ◽  
pp. 85 ◽  
Author(s):  
P. D. Shaughnessy ◽  
T. E. Dennis ◽  
P. G. Seager
Keyword(s):  
New Zealand ◽  
West Coast ◽  
South Australia ◽  
Sea Lion ◽  
The West ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Fur Seals ◽  
Fur Seal ◽  
New Zealand Fur Seal

Two seal species breed on the west coast of South Australia, the Australian sea lion, Neophoca cinerea, and the New Zealand fur seal, Arctocephalus forsteri. Aerial surveys were conducted at intervals of ~3 months between April 1995 and June 1997 to determine the breeding status of sea lions and timing of pupping seasons. Ground surveys between October 1994 and April 2004 aimed at counting sea lions and fur seals, particularly pups. In all, 27 sites were examined. Six new sea lion breeding colonies were documented, at Four Hummocks, Price, North Rocky, Dorothee, West Waldegrave and Nicolas Baudin Islands. All were found or confirmed by ground survey. Pup numbers were equivalent to 12% of the total number of pups estimated in surveys conducted from 1987 to 1992, but primarily in 1990. The sighting of brown pups on aerial surveys of Ward Island, Middle and Western Nuyts Reef supports earlier indications, based on dead pups, that they are breeding colonies. The timing of pupping seasons is not synchronous; estimates are presented for colonies between 1995 and early in 2004, with predictions to the end of 2005. The abundance estimates of sea lion pups highlight the importance of visiting a colony early in the pupping season to determine when pupping begins and ~5 months later when the maximum number of pups is expected. For the New Zealand fur seal, small numbers of pups were recorded at Dorothee, West Waldegrave and Nicolas Baudin Islands, and at Nuyts Reef. These and the previously unknown sea lion breeding colonies on the west coast of South Australia suggest that further colonies may remain to be documented. Because planning for aquaculture ventures is active in South Australia, it is important that the localities and status of sea lion and fur seal colonies be established unequivocally to ensure that the need for Prohibited Area status for islands with breeding colonies and for Marine Protected Areas around them is noted.

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