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.

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.

Stautus of the Australian sea lion, Neophoca cinerea, in the Great Australian Bight

1996 ◽  
Vol 23 (6) ◽  
pp. 741 ◽  
Author(s):  
TE Dennis ◽  
PD Shaughnessy
Keyword(s):  
Total Population ◽  
South Australia ◽  
Previous Estimate ◽  
Sea Lion ◽  
Breeding Sites ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Fur Seals ◽  
Great Australian Bight

In August 1994, a systematic survey of potential haulout sites of the Australian sea lion, Neophoca cinerea, was conducted along the coastline of the Great Australian Bight from Twin Rocks to Wilson Bluff, a distance of 206 km. A total of 289 Australian sea lions was recorded at 23 sites widely dispersed at the base of the Bunda Cliffs, hauled out on perched platforms formed by collapsed sections of cliff at various levels above the sea. Of these, 37 sea lions were recorded in a deep cave accessed from the sea. The total included 86 pups aged under 12 months, which were probably born in the region; six of these had almost completed moulting their natal pelage and were estimated to be near four months old. Only 12 New Zealand fur seals, Arctocephalus forsteri, were recorded. The Australian sea lion sites located in 1994 were surveyed again in August-September 1995, during a predicted breeding season. In this survey, a total of 284 sea lions was recorded at nine sites in South Australia and one site in Western Australia. This included 90 pups under six months of age, of which 44 were still in lanugo. Overall, we recorded 10 breeding sites and 14 haulout sites. Breeding events were recorded at one colony over three seasons and were consistent with an 18-month cycle. By extrapolating from the number of sea lion pups found in 1994, the population for the Great Australian Bight region in South Australia is estimated to be 613-774. This addition increases the previous estimate for South Australia by 9.3% and the previous total population estimate by 6.6%.

Maternal strategies of the Australian sea lion (Neophoca cinerea) at Dangerous Reef, South Australia

2011 ◽  
Vol 59 (1) ◽  
pp. 54 ◽  
Author(s):  
Andrew D. Lowther ◽  
Simon D. Goldsworthy
Keyword(s):  
South Australia ◽  
Maternal Investment ◽  
Milk Lipid ◽  
Resource Exploitation ◽  
Sea Lion ◽  
Breeding Sites ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Spatial Differences ◽  
Pup Growth

Maternal strategies of otariid seals reflect the optimisation between resource exploitation and offspring provisioning driven across spatially separated foraging and nursing grounds. Intercolony variation in the expression of maternal strategies may represent temporal and spatial differences in resource availability, intraspecies competition or differences in life-history traits. The current study describes maternal strategies of the Australian sea lion at the largest breeding colony of the species (Dangerous Reef) and a comparative analysis was performed with data collected 16 years earlier at Seal Bay (Kangaroo Island). Significant differences in maternal strategies were characterised by lower milk lipid content (21.0 versus 28.9%), abbreviated periods onshore (0.93 versus 1.63 days) and slower pup growth rates (0.09–0.12 kg day–1) at Dangerous Reef. These data suggest flexibility in the expression of maternal investment between breeding sites and support the hypothesis of localised adaptation

Louse infestations of the Australian sea lion Neophoca cinerea.

2007 ◽  
Vol 29 (1) ◽  
pp. 103 ◽  
Author(s):  
R.R. McIntosh ◽  
M.D. Murray
Keyword(s):  
Sea Lion ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Australian Sea Lion

Sea lions (Neophoca cinerea) at several South Australian islands were infested with the anopluran louse Antarctophthirus microchir.

scholarly journals Colony Location and Captivity Influence the Gut Microbial Community Composition of the Australian Sea Lion (Neophoca cinerea)

2016 ◽  
Vol 82 (12) ◽  
pp. 3440-3449 ◽  
Author(s):  
Tiffany C. Delport ◽  
Michelle L. Power ◽  
Robert G. Harcourt ◽  
Koa N. Webster ◽  
Sasha G. Tetu
Keyword(s):  
Microbial Community ◽  
Marine Mammals ◽  
Animal Health ◽  
Sea Lion ◽  
Content Type ◽  
Sea Lions ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Captive Populations ◽  
Gut Microbial Community

ABSTRACTGut microbiota play an important role in maintenance of mammalian metabolism and immune system regulation, and disturbances to this community can have adverse impacts on animal health. To better understand the composition of gut microbiota in marine mammals, fecal bacterial communities of the Australian sea lion (Neophoca cinerea), an endangered pinniped with localized distribution, were examined. A comparison of samples from individuals across 11 wild colonies in South and Western Australia and three Australian captive populations showed five dominant bacterial phyla:Firmicutes,Proteobacteria,Bacteroidetes,Actinobacteria, andFusobacteria. The phylumFirmicuteswas dominant in both wild (76.4% ± 4.73%) and captive animals (61.4% ± 10.8%), whileProteobacteriacontributed more to captive (29.3% ± 11.5%) than to wild (10.6% ± 3.43%) fecal communities. Qualitative differences were observed between fecal communities from wild and captive animals based on principal-coordinate analysis. SIMPER (similarity percentage procedure) analyses indicated that operational taxonomic units (OTU) from the bacterial familiesClostridiaceaeandRuminococcaceaewere more abundant in wild than in captive animals and contributed most to the average dissimilarity between groups (SIMPER contributions of 19.1% and 10.9%, respectively). Differences in the biological environment, the foraging site fidelity, and anthropogenic impacts may provide various opportunities for unique microbial establishment in Australian sea lions. As anthropogenic disturbances to marine mammals are likely to increase, understanding the potential for such disturbances to impact microbial community compositions and subsequently affect animal health will be beneficial for management of these vulnerable species.IMPORTANCEThe Australian sea lion is an endangered species for which there is currently little information regarding disease and microbial ecology. In this work, we present an in-depth study of the fecal microbiota of a large number of Australian sea lions from geographically diverse wild and captive populations. Colony location and captivity were found to influence the gut microbial community compositions of these animals. Our findings significantly extend the baseline knowledge of marine mammal gut microbiome composition and variability.

Milk composition of Australian sea lions, Neophoca cinerea: variability in lipid content

1991 ◽  
Vol 69 (10) ◽  
pp. 2556-2561 ◽  
Author(s):  
Maria B. Kretzmann ◽  
Daniel P. Costa ◽  
Lesley V. Higgins ◽  
D. J. Needham
Keyword(s):  
Lipid Content ◽  
Milk Fat ◽  
Milk Composition ◽  
Fat Content ◽  
Sea Lion ◽  
Sea Lions ◽  
Milk Samples ◽  
Stage Of Lactation ◽  
Neophoca Cinerea ◽  
Australian Sea Lion

Thirty-eight milk samples collected over three seasons from 23 individual Australian sea lions (Neophoca cinerea) were analyzed. Mean milk composition was 25.4% lipid (± 9.3% SD), 62.4% water (± 8.1%), 10.5% protein (± 2.2%), and 0.9% ash (± 0.2%). Milk composition appeared to vary considerably among females, and occasionally between successive samples from the same individual. Milk fat content was not correlated with pup age (stage of lactation), female mass, length of the preceding foraging trip, or time onshore prior to milk collection. The relatively low lipid content of Australian sea lion milk compared with that of some other otariid seals is consistent with the hypothesis that otariid females making relatively short trips to sea produce milk with lower fat content than those species which make foraging trips of longer duration.

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.

Morphology, sex ratio and cause of death in Australian sea lion (Neophoca cinerea) pups

2013 ◽  
Vol 35 (1) ◽  
pp. 93 ◽  
Author(s):  
Rebecca R. McIntosh ◽  
Clarence W. Kennedy
Keyword(s):  
Sex Ratio ◽  
Cause Of Death ◽  
Histopathological Examination ◽  
Good Condition ◽  
Parasitic Infection ◽  
Sea Lion ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Males And Females ◽  
Breeding Seasons

During a study of the demographics of the Australian sea lion (Neophoca cinerea), the sex ratio and morphology were obtained from 128 pups at Seal Bay Conservation Park over three breeding seasons (2002–03, 2004 and 2005–06). Gross necropsies were also performed. Dead pups were small and young, averaging 8.0 and 7.0 kg in weight, and 75.2 and 71.3 cm in length, for males and females respectively, only 1.8 kg heavier and 6.7 cm longer than newborn pups. There was no sex bias in the dead pups overall or in each cause of death classification. In 49% of mortalities, cause of death could not be inferred from gross necropsy and pups appeared in good condition. In pups in which cause of death was inferred, trauma inflicted by conspecifics was the primary result in both males and females (31.6%), followed by emaciation (10.4%), stillbirth or premature birth (7.6%) and possible shark attack (1.4%). Histopathological examination of tissues and other investigations would be required to determine whether other factors, such as disease or parasitic infection, and pollutant contamination contribute to pup mortality.

The Female Reproductive-Tract of the Australian Sea Lion, Neophoca-Cinerea (Peron, 1816) (Carnivora, Otariidae)

1991 ◽  
Vol 39 (3) ◽  
pp. 351 ◽  
Author(s):  
RA Tedman
Keyword(s):  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
Breeding Cycle ◽  
Embryonic Diapause ◽  
Sea Lion ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Uterine Mucosa ◽  
Breeding Seasons ◽  
Uterine Glands

This first account of the morphology of the female reproductive tract of the Australian sea lion, Neophoca cinerea, is based on examination of 15 specimens. The morphology of the female reproductive tract is similar in most respects to that in other pinniped species; only features peculiar to the species are described. The Y-shaped, bicornuate uterus is for the most part septate, but has a common uterine canal that is relatively much longer than that in other otariids. The uterine mucosa of newborns is slightly hypertrophied and regresses considerably by 3 weeks postpartum. During the embryonic diapause the uterine mucosa has serrated luminal epithelium, coiled uterine glands, and tall luminal and glandular epithelia. The mucosa of the adult vagina decreases in thickness from 100-mu-m at about 2 weeks postpartum to 20-mu-m 14.5 weeks postpartum, indicative of the regressive phase typical of the delay period in other pinnipeds. The urethral meatus lacks urinary papillae, unlike most other pinnipeds. A relatively large clitoris is present, and an os clitoridis was collected from one old individual. A monoestrous cycle seemed to occur in four animals, but a polyoestrous cycle is suspected in at least one individual. Ovulation occurs from alternate ovaries in successive pregnancies. Corpora albicantia are retained for at least three breeding seasons and probably longer. Implantation occurs in the midsection of the uterine cornu, ipsilateral to the ovary that released the egg. The maximum period of embryonic diapause cannot be ascertained from the available data, although a delay of about 8-9 months is possible if the breeding cycle (pregnancy cycle) lasts about 18 months.

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