scholarly journals The condition conundrum: application of multiple condition indices to the dusky shark Carcharhinus obscurus

2009 ◽  
Vol 380 ◽  
pp. 199-212 ◽  
Author(s):  
NE Hussey ◽  
DT Cocks ◽  
SFJ Dudley ◽  
ID McCarthy ◽  
SP Wintner
Keyword(s):  
Dusky Shark ◽  
Carcharhinus Obscurus ◽  
Condition Indices

New polymorphic microsatellite loci revealed for the dusky shark Carcharhinus obscurus through Ion Proton double-digest RAD sequencing

2018 ◽  
Vol 45 (6) ◽  
pp. 2759-2763 ◽  
Author(s):  
Simo N. Maduna ◽  
Charné Rossouw ◽  
Ruhan Slabbert ◽  
Sabine P. Wintner ◽  
Charlene da Silva ◽  
...  
Keyword(s):  
Microsatellite Loci ◽  
Rad Sequencing ◽  
Dusky Shark ◽  
Carcharhinus Obscurus ◽  
Ion Proton ◽  
Polymorphic Microsatellite

Characterisation and cross-amplification of 21 novel microsatellite loci for the dusky shark, Carcharhinus obscurus

2015 ◽  
Vol 7 (4) ◽  
pp. 909-912 ◽  
Author(s):  
D. C. Blower ◽  
S. Corley ◽  
J. P. Hereward ◽  
C. R. Riginos ◽  
J. R. Ovenden
Keyword(s):  
Microsatellite Loci ◽  
Cross Amplification ◽  
Dusky Shark ◽  
Carcharhinus Obscurus

Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals

1999 ◽  
Keyword(s):  
Life History ◽  
Live Weight ◽  
Marine Species ◽  
Population Increase ◽  
Natural Mortality ◽  
Marine Animals ◽  
Southwestern Australia ◽  
Average Litter Size ◽  
Dusky Shark ◽  
Carcharhinus Obscurus

<em>Abstract.</em> —An assessment of the dusky shark <em>Carcharhinus obscurus </em> fishery in southwestern Australia was undertaken using demographic techniques. Current annual catches of <em>C. obscurus </em> by the fishery are 500–700 metric tons (live weight), most of which are recently born individuals (age-0). The best estimates of life history parameters indicate that the annual rate of population increase is 4.3% when unfished and that the <EM>F</EM><sub> MSY</sub> is 0.021. Tests indicate that the results are most sensitive to changes in values of natural mortality and age at maturity. Changes to the values of average litter size, reproductive periodicity, and longevity had little effect on the results. The inclusion in the analysis of age-specific exploitation rates from a tagging study indicate that at current levels of fishing the <em>C. obscurus </em> population in southwestern Australia is most likely to be sustainable. However, it must be noted that there is some unquantified mortality of older year-classes due to fishing operations outside of the managed fishery. The results indicate that it is possible to exploit long-lived, late-maturing, slow-reproducing marine animals by targeting the youngest age-classes. The results are discussed in relation to the dusky shark fishery in southwestern Australia and the exploitation of other long-lived marine species.

Population metrics and movement of two sympatric carcharhinids: a comparison of the vulnerability of pelagic sharks of the southern Australian gulfs and shelves

2013 ◽  
Vol 64 (1) ◽  
pp. 20 ◽  
Author(s):  
P. J. Rogers ◽  
C. Huveneers ◽  
S. D. Goldsworthy ◽  
W. W. L. Cheung ◽  
G. K. Jones ◽  
...  
Keyword(s):  
Sympatric Species ◽  
White Shark ◽  
Logic Model ◽  
Shark Species ◽  
Carcharodon Carcharias ◽  
Marine Predators ◽  
Management Measures ◽  
Dusky Shark ◽  
Carcharhinus Obscurus ◽  
Relative Vulnerability

The dusky shark Carcharhinus obscurus and the bronze whaler Carcharhinus brachyurus are large-bodied, marine predators that inhabit coastal and shelf waters of southern Australia. C. obscurus is considered to be among the most vulnerable pelagic sharks to overexploitation. This study focussed on population metrics and movement patterns of these sympatric species. Litters from two pregnant C. brachyurus were examined; these comprised 20 and 24 embryos, respectively. Tagging data indicated that 75% of whaler sharks tagged in this region by recreational fishers were juveniles, and 58% of recaptures occurred within 50 km of the tagging locations. Fishery catch samples comprised 99% juvenile C. brachyurus and C. obscurus. Our findings suggested that semi-protected gulf waters represented ecologically significant habitats of juveniles. A fuzzy-logic model showed that in terms of relative vulnerability to fishing, C. brachyurus ranked in the mid to lower end of the spectrum, when compared with six sympatric pelagic shark species, including the white shark, Carcharodon carcharias. Our findings emphasised a need for improvement to management measures for these carcharhinids, which are likely to play a significant role in the functioning of the temperate gulf and shelf ecosystems.

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