. Predation on Australian sea lions Neophoca cinerea by white sharks Carcharodon carcharias in South Australia

2007 ◽  
Vol 29 (1) ◽  
pp. 69 ◽  
Author(s):  
PD, Shaughnessy ◽  
M Berris ◽  
T. E. Dennis
Keyword(s):  
South Australia ◽  
Stomach Contents ◽  
White Shark ◽  
Carcharodon Carcharias ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Adult Females ◽  
Gill Net ◽  
The Mean ◽  
Pass Through

From January 1988 to December 2002, 182 Australian sea lions Neophoca cinerea with injuries attributable to white sharks Carcharodon carcharias were recorded in the N. cinerea colony at Seal Bay, Kangaroo Island. The mean number per month was 1.0 (s.d. 1.3), and the number per calendar year varied from 5 to 25 (mean 12.1, s.d. 6.1). The incidence was highest in summer (December to February) and autumn (March to May). The month with the greatest incidence of injured sea lions was January, when it was 17% of the total. This coincides with the higher proportion of white shark records around Kangaroo Island in summer and autumn than in other seasons (Bruce 1992). Adult female and juvenile sea lions were attacked most frequently, with 38% and 26%, respectively. Adult females pass through the waters near the colony more frequently than other sea lions, which makes them more susceptible than other age-sex groups to attacks by white sharks. Most (42%) injuries were to the head and central parts of the sea lions' bodies and 39% were to the rear of their bodies ('rear trunk' and 'hind flippers' areas). The stomach contents of a white shark caught in a bottom-set monofilament gill-net at Cape Gantheaume, Kangaroo Island in April 1992 included two N. cinerea pups aged 10-12 months. They formed about 75% of the shark?s stomach contents.

Breeding and longevity in captive Australian sea lions Neophoca cinerea at zoos and aquaria in Australia: 1965-2003.

2006 ◽  
Vol 28 (1) ◽  
pp. 65 ◽  
Author(s):  
J. K. Ling ◽  
C. Atkin ◽  
A. Barnes ◽  
A. Fischer ◽  
M. Guy ◽  
...  
Keyword(s):  
New South ◽  
South Australia ◽  
Embryonic Diapause ◽  
Birth Intervals ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
South Wales ◽  
In Captivity ◽  
In The Wild ◽  
The Mean

Australian sea lions (Neophoca cinerea) are known to have been kept in aquaria and zoos in Australia since 1965. During that time at least 41 births were recorded, of which 19 were in Adelaide, 15 at Adelaide Zoo and 4 at Marineland of South Australia. The mean interval between successive births in Adelaide was 538.9 � 9.5 days (18.0 months; n = 10) and the mean assumed pregnancy period, including embryonic diapause, was 536.0 � 11.4 days (17.9 months; n = 9). The mean interval between parturition and presumed successful mating was 8.4 � 1.6 days (n = 5). Births occurred in all months except January, June, August and December. Figures for New South Wales and Queensland establishments are too small and scattered over time for any pregnancy periods or birth intervals to be determined. Likewise, latitudinal differences, if any, were not evident, because of the paucity of data from these more northerly places. One female at the Adelaide Zoo produced 8 pups between 1986 and 1997; she is still alive after 22 years in captivity. The youngest known-age (captive-born) female was 4 years, 8 months old when she gave birth to her first pup; and the oldest female in captivity to give birth to a pup was aged approximately 21 years, 8 months. The longest recorded captive period for a female was more than 25 years by 31 December 2003, and for a male it was 21 years, 11 months. A captive-bred female was still alive after 18 years, 2 months, 24 days; another such female died aged 18 years, 2 months, 18 days. These life spans appear to be similar to those that meagre data suggest for tagged N. cinerea in the wild.

Pup numbers of the Australian sea lion (Neophoca cinerea) at The Pages Islands, South Australia, over two decades

2013 ◽  
Vol 61 (2) ◽  
pp. 112 ◽  
Author(s):  
Peter D. Shaughnessy ◽  
Simon D. Goldsworthy ◽  
Paul Burch ◽  
Terry E. Dennis
Keyword(s):  
Population Size ◽  
South Australia ◽  
Sea Lion ◽  
Breeding Colony ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Gill Net ◽  
Low Levels ◽  
Breeding Seasons

The Australian sea lion is an Australian endemic, restricted to South Australia and Western Australia, with 86% of the population in South Australia. It was listed under the Commonwealth Environment Protection and Biodiversity Conservation Act as Vulnerable in February 2005, and the International Union for the Conservation of Nature has listed it as Endangered. Sea lions are taken as bycatch in the gill-net fishery for school shark and gummy shark, and the risk of extinction of breeding colonies is high even from low levels of bycatch. We assessed trends in pup population size at The Pages Islands, a large breeding colony in South Australia. Pup abundance was estimated by direct counting of live and dead pups; the maximum count in each breeding season was used for trend analysis. The average of direct counts of pups in 14 breeding seasons between 1989–90 and 2009–10 was 473 (s.d. = 58.4). There was no trend in pup numbers, contrasting with two other large colonies: Seal Bay, Kangaroo Island (decreasing), and Dangerous Reef (increasing since 2000). The Australian Sea Lion Management Strategy of the Australian Fisheries Management Authority aims to reduce sea lion bycatch in the shark fishery; a key item is a fishery closure around each breeding colony in South Australia. Implementation of the closure around The Pages should lower the risk of bycatch of its sea lions with foraging areas that previously overlapped with the fishery and should allow the colony’s population size to increase.

Rate of passage of digesta through the alimentary tract of the New Zealand fur seal (Arctocephalus forsteri) and the Australian sea lion (Neophoca cinerea) (Carnivora : Otariidae)

1999 ◽  
Vol 47 (2) ◽  
pp. 193 ◽  
Author(s):  
B. Bodley ◽  
the late J. R. Mercer ◽  
M. M. Bryden
Keyword(s):  
New Zealand ◽  
Feeding Time ◽  
Sea Lions ◽  
First Feeding ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Fur Seals ◽  
The Mean ◽  
Initial Recovery ◽  
New Zealand Fur Seal

The inert marker titanium dioxide was added to the food of two male New Zealand fur seals (Arctocephalus forsteri) and three Australian sea lions (Neophoca cinerea) in Taronga Zoo, Sydney, in a series of 15 trials. The enclosures were checked constantly during daylight hours, and defaecation times and location of samples noted. Samples were collected at feeding times, at approximately 0930, 1300 and 1500 hours. During the night the animals were checked at 30-min intervals, the location of samples noted, and samples collected at the first feeding time next morning. Faecal collections were made for up to 50 h after dosing. Marker concentrations in faecal dry matter were determined and mean retention times calculated from the mean concentration-time curves. The mean time between dosing and first recovery of marker (Initial Recovery Time) was 4 h for A. forsteri and 6.5 h for N. cinerea. Mean retention time, a better index of rate of passage of digesta, was 14.6 h for A. forsteri and 14.9 h for N. cinerea. Thus, the marker concentration curves indicated a rapid rate of food transit through the gastrointestinal tract, as has been observed in several (but not all) pinniped species.

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.

Dietary analysis of regurgitates and stomach samples from free-living Australian sea lions

2006 ◽  
Vol 33 (8) ◽  
pp. 661 ◽  
Author(s):  
Rebecca R. McIntosh ◽  
Brad Page ◽  
Simon D. Goldsworthy
Keyword(s):  
Prey Species ◽  
South Australia ◽  
Rock Lobster ◽  
Sea Lion ◽  
Free Living ◽  
Dietary Analysis ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Sepia Apama

Dietary remains recovered from Australian sea lion (Neophoca cinerea) digestive tracts and regurgitate samples from Seal Bay (Kangaroo Island, South Australia) were used to identify prey species consumed. Four of eight digestive tracts collected (50%) contained prey items located only in the stomach. On the basis of biomass reconstruction of cephalopod prey remains, octopus contributed 40% of the biomass in the samples, giant cuttlefish (Sepia apama) contributed 30% and ommastrephid squids contributed 14% biomass. The remains of several fish species were found in the samples: leatherjacket (Monocanthidae), flathead (Platycephalus sp.), swallowtail (Centroberyx lineatus), common bullseye (Pempheris multiradiata), southern school whiting (Sillago flindersi) and yellowtail mackerel (Trachurus novaezelandiae). Southern rock lobster (Jasus edwardsii) and swimming crab (Ovalipes australiensis) carapace fragments, little penguin (Eudyptula minor) feathers and bones and shark egg cases (oviparous species and Scyliorhinidae sp.) were also identified.

Assessing the use of milk fatty acids to infer the diet of the Australian sea lion (Neophoca cinerea)

2009 ◽  
Vol 36 (2) ◽  
pp. 169 ◽  
Author(s):  
A. M. M. Baylis ◽  
D. J. Hamer ◽  
P. D. Nichols
Keyword(s):  
South Australia ◽  
Satellite Tracking ◽  
Sea Lion ◽  
Milk Fatty Acids ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Fa Composition ◽  
Pinniped Species ◽  
Management Plans

Information on the diet of threatened species is important in devising appropriate management plans to ensure their conservation. The Australian sea lion (Neophoca cinerea) is Australia’s only endemic and globally one of the least numerous pinniped species. However, dietary information is currently limited because of the difficulty in using traditional methods (identification of prey hard parts from scats, regurgitates and stomach samples) to reliably provide dietary information. The present study assessed the use of fatty acid (FA) analysis to infer diet using milk samples collected from 11 satellite tracked Australian sea lions from Olive Island, South Australia. Satellite tracking revealed that females foraged in two distinct regions; ‘inshore’ regions characterised by shallow bathymetry (10.7 ± 4.8 m) and ‘offshore’ regions characterised by comparatively deep bathymetry (60.5 ± 13.4 m). Milk FA analysis indicated significant differences in the FA composition between females that foraged inshore compared with those that foraged offshore. The greatest differences in relative levels of individual FAs between the inshore and offshore groups were for 22 : 6n-3 (6.5 ± 1.2% compared with 16.5 ± 1.9% respectively), 20 : 4n-6 (6.1 ± 0.7 compared with 2.5 ± 0.7 respectively) and 22 : 4n-6 (2.4 ± 0.2% compared with 0.8 ± 0.2% respectively). Using discriminant scores, crustacean, cephalopod, fish and shark-dominated diets were differentiated. The discriminant scores from Australian sea lions that foraged inshore indicated a mixed fish and shark diet, whereas discriminant scores from Australian sea lions that foraged offshore indicated a fish-dominated diet, although results must be interpreted with caution due to the assumptions associated with the prey FA dataset. FA analysis in combination with satellite tracking proved to be a powerful tool for assessing broad-scale spatial dietary patterns.

scholarly journals A Rapid Assessment Technique to Assist Management of the White Shark (Carcharodon Carcharias) Cage Dive Industry, South Australia

2013 ◽  
Vol 6 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Russell Bradford ◽  
Rachel Robbins
Keyword(s):  
Rapid Assessment ◽  
Economic Value ◽  
South Australia ◽  
White Shark ◽  
Rapid Expansion ◽  
Conservative Estimate ◽  
Participation Rates ◽  
Carcharodon Carcharias ◽  
Assessment Technique ◽  
The Future

Port Lincoln, South Australia is the departure port for the only white shark, Carcharodon carcharias, cage dive industry in Australia. Established in the early 1960’s as a niche tourism venture, the industry has recently undergone a rapid expansion to accommodate greater passenger numbers, more tourism operators, and additional infrastructure aimed at capturing a greater proportion of the tourist dollar. However, to date, there has been no assessment of growth in the industry. We have used the operator logbook system, introduced in 2000, as the basis for a rapid assessment of the maturity as well as a conservative estimate of the economic value of the industry, with a focus on 2011. From the logbook system the number of days on-site has increased from an average of 67 days per year prior to 2007 to 287 days on-site in 2011. In 2011 the industry accommodated approximately 5200 passengers with a direct domestic expenditure estimated to be in excess of 6 million AUD. Changes in shark behaviour have been observed following the increase in days on-site. The white shark cage dive industry has reached a stage in its development where increased management is required in order to ensure a viable industry into the future. The rapid assessment technique described herein will allow managers to track changes in cage dive participation rates and quickly respond to changes in the industry.

scholarly journals Establishing tourism guidelines for viewing Australian Sea Lions Neophoca cinerea at Seal Bay Conservation Park, South Australia

2008 ◽  
pp. 225-232 ◽  
Author(s):  
Terijo Lovasz ◽  
David B. Croft ◽  
Peter Banks
Keyword(s):  
South Australia ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Conservation Park

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.

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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