Pup Growth and Maternal Care in New Zealand Fur Seals, Arctocephalus forsteri, at Maatsuyker Island, Tasmania

1997 ◽  
Vol 24 (3) ◽  
pp. 307 ◽  
Author(s):  
Mary-Anne Lea ◽  
Mark. A. Hindell
Keyword(s):  
New Zealand ◽  
Interannual Variability ◽  
Body Mass ◽  
Growth Rates ◽  
Maternal Care ◽  
Early Growth ◽  
Fur Seals ◽  
Fur Seal ◽  
New Zealand Fur Seal ◽  
Pup Growth

The growth, maternal attendance and sucking behaviour of 11 New Zealand fur seal pups, Arctocephalus forsteri, on Maatsuyker Island, Tasmania, were studied during the first six months of lactation. Early growth rates (0–50 days) ranged from 78 to 138 g day-1 and were amongst the highest recorded for any fur seal. Male pups from Maatsuyker Island in 1993 grew at double the rate reported from Kangaroo Island in 1989 and 1990. Growth of pups was influenced by the attendance behaviour of mothers. Mothers that spent relatively long periods at sea had pups that grew more slowly. The proportion of time spent sucking by pups decreased during the attendance period of mothers. Distinct interannual variability was also determined for body masses of pups weighed in March in five successive years, 1990–94, with mean body mass differing by up to 20% between years.

Rearing two New Zealand fur seal (Arctocephalus forsteri) pups to weaning

2008 ◽  
Vol 56 (1) ◽  
pp. 33 ◽  
Author(s):  
Sacha A. Dowell ◽  
Laura J. Boren ◽  
Sandra S. Negro ◽  
Chris G. Muller ◽  
Abigail K. Caudron ◽  
...  
Keyword(s):  
New Zealand ◽  
Growth Rates ◽  
Recognition System ◽  
The Other ◽  
Energy Costs ◽  
Rare Occurrence ◽  
Lower Mass ◽  
Fur Seals ◽  
Fur Seal ◽  
New Zealand Fur Seal

The rearing of two pups to weaning is a rare occurrence in pinnipeds and in many cases it remains unknown whether it is a result of twinning or fostering. This study followed two cases where female New Zealand fur seals (Arctocephalus forsteri) raised two pups, at a colony in Kaikoura, New Zealand. Maternal attendance behaviour was observed, mass and condition of the pups were measured and genetic samples were collected to assess relatedness. In one case, the female gave birth to twins, while the other case was found to be fostering of a second pup. In both cases, the filial pups of each female exhibited significantly lower mass, condition and growth rates than the colony average. The twins’ mother reared both pups to weaning and did not appear to spend a different amount of time ashore compared with single-pup mothers. The current study confirms both fostering and twinning in New Zealand fur seals, with the potential for successfully raising the pups to weaning, despite their well developed recognition system and the energy costs involved.

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.

Interannual variation in birth mass and postnatal growth rate of Juan Fernández fur seals

1998 ◽  
Vol 76 (5) ◽  
pp. 978-983 ◽  
Author(s):  
Hugo Ochoa-Acuña ◽  
John M Francis ◽  
Daryl J Boness
Keyword(s):  
Growth Rate ◽  
Body Mass ◽  
Growth Rates ◽  
Interannual Variation ◽  
Postnatal Growth ◽  
Male And Female ◽  
Fur Seals ◽  
Fur Seal ◽  
Attendance Pattern

The objectives of this study were to establish body mass at birth, postnatal growth rate, and the factors that influence these parameters for the Juan Fernández fur seal, Arctocephalus philippii. Females of this species have an unusual attendance pattern in which foraging trips and shore visits last, on average, 12.3 and 5.3 days, respectively. Pup mass was obtained from cohorts born during the reproductive seasons in 1988 through 1992. Birth masses of male and female pups were significantly different, averaging 6.1 and 5.5 kg, respectively (F = 13.2, P < 0.0003, n = 238). Birth masses also differed among cohorts, being lowest in 1992 and highest in 1990. During the first 2 months of life, male and female pups grew at the same rate (79 ± 61.5 g · day-1 (mean ± SD); F[1] = 0.03, P = 0.8562). Interannual differences in growth rate during the first month were significant (F[4] = 8.14, P < 0.0001), as was the interaction between month and year effects (F[2] = 6.81, P = 0.0012). Growth rates for the 1990 cohort were lower than those in all other years except 1992. Birth masses and postnatal growth rates of Juan Fernández fur seal pups are comparable to those of other otariid species.

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.

Maternal strategies of the New Zealand fur seal: evidence for interannual variability in provisioning and pup growth strategies

2006 ◽  
Vol 54 (1) ◽  
pp. 31 ◽  
Author(s):  
Simon D. Goldsworthy
Keyword(s):  
New Zealand ◽  
South Australia ◽  
Growth Patterns ◽  
Growth Strategies ◽  
Male And Female ◽  
Maternal Expenditure ◽  
Fur Seal ◽  
Weaning Age ◽  
New Zealand Fur Seal ◽  
Pup Growth

Maternal attendance, nursing behaviour, pup growth and weaning age were investigated in the New Zealand fur seal (Arctocephalus forsteri) at Kangaroo Island, South Australia. Foraging trips to sea increased throughout lactation (5.9–9.8 days), while the duration of shore attendance bouts (1.7 ± 0.7 days) remained unchanged, resulting in time ashore declining from 24% to 14% throughout lactation. Mothers with sons made longer foraging trips than mothers with daughters throughout lactation and, as a consequence, maternal time ashore was less for sons (21%) than for daughters (28%). Pups maintained an overall sucking-rate of 1.4 h day–1 throughout their mothers’ lactation, by sucking more frequently and for longer periods as their mother became less available. Because mothers with daughters were ashore more frequently, the overall sucking-rate of females (1.7 h day–1) was greater than that of male pups (1.1 h day–1). The growth patterns of male and female pups from two cohorts were similar, but males grew faster and weaned heavier in one of the years. Age at weaning was ~285 days (9.4 months). This study indicates some significant differences in the nature of maternal expenditure in male and female pups, and the growth strategies used by pups both within and between years.

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.

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