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.

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.

Functional-Morphology of the Alimentary-Tract of the Australian Sea-Lion, Neophoca-Cinerea

1987 ◽  
Vol 35 (3) ◽  
pp. 219 ◽  
Author(s):  
KC Richardson ◽  
NJ Gales
Keyword(s):  
Alimentary Tract ◽  
Fine Particles ◽  
Stomach Contents ◽  
Coarse Particles ◽  
Pyloric Antrum ◽  
Sea Lion ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Acting In Concert ◽  
Pyloric Canal

The form and topographic relationships of the alimentary tract of Neophoca cinerea is described based on dissection and radiography. A highly distensible oesophagus enters the dorsum of a large J-shaped stomach. The small intestine is long, circa 20 m, and the large intestine short, circa 1.2 m. Marker pellets (approximate diameter 1 or 3 mm) administered orally were generally found in faecal deposits containing, principally, coarse particles, i.e. of diameter greater than 1.2 mm. Most faecal deposits consisted of fine particles, i.e. with a diameter primarily of less than 1.2 mm. About 50% of the large markers remained in the alimentary tract for more than 6 days. A pyloric torus acting in concert with the patterns of pyloric peristalsis may prevent or restrict the passage of markers through the pyloric canal. Examination of the stomach contents from six animals showed that items of low digestibility, such as squid beaks and crayfish exoskeletons, were retained in the pyloric antrum.

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.

Breeding age of a captive male Australian sea lion, Neophoca cinerea, at the Adelaide Zoo.

2007 ◽  
Vol 29 (1) ◽  
pp. 101 ◽  
Author(s):  
J.K. Ling ◽  
M. Guy
Keyword(s):  
Sea Lion ◽  
Neophoca Cinerea ◽  
Australian Sea Lion

A captive 3 year 2 month old female sea lion (Neophoca cinerea) mated with a 3 year 3-6 month old male and she gave birth 530 days later.

Delayed onset of vocal recognition in Australian sea lion pups (Neophoca cinerea)

2009 ◽  
Vol 96 (8) ◽  
pp. 901-909 ◽  
Author(s):  
Benjamin J. Pitcher ◽  
Heidi Ahonen ◽  
Robert G. Harcourt ◽  
Isabelle Charrier
Keyword(s):  
Sea Lion ◽  
Delayed Onset ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Vocal Recognition

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.

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