The endangered Australian sea lion extensively overlaps with and regularly becomes by-catch in demersal shark gill-nets in South Australian shelf waters

2013 ◽  
Vol 157 ◽  
pp. 386-400 ◽  
Author(s):  
D.J. Hamer ◽  
S.D. Goldsworthy ◽  
D.P. Costa ◽  
S.L. Fowler ◽  
B. Page ◽  
...  
Keyword(s):  
Sea Lion ◽  
Gill Nets ◽  
Australian Sea Lion ◽  
By Catch

First observations of operational interactions between bottom-trawling fisheries and South American sea lion, Otaria flavescens in south-central Chile

2012 ◽  
Vol 93 (2) ◽  
pp. 489-494 ◽  
Author(s):  
Pablo Reyes ◽  
Rodrigo Hucke-Gaete ◽  
Juan Pablo Torres-Florez
Keyword(s):  
South American ◽  
The South ◽  
Sea Lion ◽  
Central Chile ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
South American Sea Lion ◽  
South Central ◽  
By Catch ◽  
Working Day

This paper presents results of a study conducted on the trawling industrial fishery fleet of Merluccius gayi in south-central Chile, and the resulting interactions with the South American sea lion (Otaria flavescens). This study is based on observations made during September 2004, when incidental sea lion catch in the trawls was 6.3 sea lions/working day (1.2 sea lions/trawl−1). A total of 82 animals were incidentally caught, of which 12 were found dead, and the 70 remaining suffered from internal bleeding and/or fractures as a result of their capture. 83.3% of the fatalities occurred during nocturnal trawls, which comprise 30% of all observed trawls. Possible mechanisms of sea lion take are discussed. This note presents the first records of sea lions incidental by-catch by the trawler fleet along the south-east Pacific coast of Chile.

Shark control: experimental fishing with baited drumlines

1998 ◽  
Vol 49 (7) ◽  
pp. 653 ◽  
Author(s):  
S. F. J. Dudley ◽  
R. C. Haestier ◽  
K. R. Cox ◽  
M. Murray
Keyword(s):  
Optimal Solution ◽  
Control Programme ◽  
Shark Species ◽  
Gill Nets ◽  
Carcharhinus Leucas ◽  
Local Reduction ◽  
Shark Attacks ◽  
By Catch ◽  
Catch Rates ◽  
Physical Environmental Factors

Protective gill-nets (shark nets) have been successful in reducing the frequency of shark attacks on the coast of KwaZulu-Natal (KZN), South Africa, since 1952. This is achieved primarily through a local reduction in numbers of large sharks. Yet the nets are non-selective in terms of shark species caught and take a by-catch of dolphins, sea turtles, batoids and teleosts. Baited lines, or drumlines, as used in the Queensland shark control programme, were tested as possible alternatives to gill-nets. They demonstrated greater species selectivity for sharks and also a reduced by-catch of non-shark animals. The shark catch included the three species responsible for most shark attacks on the KZN coast, Carcharhinus leucas, Galeocerdo cuvier and Carcharodon carcharias. The probability of the bait being scavenged, or a shark being caught, was modelled in relation to a number of physical environmental factors. Although there was insufficient variability in the effort data for a quantitative comparison of catch rates between nets and drumlines, the results suggested that an optimal solution may be to deploy a combination of nets and drumlines.

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
Sign in / Sign up

Export Citation Format

Share Document