Conservation: Goldilocks Nations for Restoring Reef Sharks

Sharks and rays are a global conservation concern with an increasing number of species considered at risk of extinction, mostly due to overfishing. Although the recreational harvest of sharks and rays is poorly documented and generally minimal, it can be comparable to the commercial harvest. In this study, we quantified the recreational harvest of sharks and rays in Western Australia, a region with a marine coastline greater than 20,000 km. A total of 33 species/taxonomic groups were identified, with the harvest dominated by dusky and bronze whalers, blacktip reef sharks, gummy sharks, Port Jackson sharks, wobbegongs, and rays and skates. Eighty-five percent of individuals were released with an unknown status (alive or dead). We found a latitudinal gradient of species composition, with tropical and subtropical species of the genus Carcharhinus dominating in the north and temperate species from a range of families dominating in the south. Overall, our findings showed that the recreational harvest was negligible when compared with commercial landings.

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Dead tired: evaluating the physiological status and survival of neonatal reef sharks under stress

Conservation Physiology ◽

10.1093/conphys/coy053 ◽

2018 ◽

Vol 6 (1) ◽

Cited By ~ 7

Author(s):

Ian A Bouyoucos ◽

Ornella C Weideli ◽

Serge Planes ◽

Colin A Simpfendorfer ◽

Jodie L Rummer

Keyword(s):

Physiological Status ◽

Reef Sharks

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Relations between morphology, buoyancy and energetics of requiem sharks

Royal Society Open Science ◽

10.1098/rsos.160406 ◽

2016 ◽

Vol 3 (10) ◽

pp. 160406 ◽

Cited By ~ 18

Author(s):

Gil Iosilevskii ◽

Yannis P. Papastamatiou

Keyword(s):

Body Temperature ◽

Negative Selection ◽

Swimming Performance ◽

Ontogenetic Changes ◽

Cost Of Transport ◽

Pectoral Fins ◽

Confined Spaces ◽

Reef Sharks ◽

The Cost ◽

Derivatives Of

Sharks have a distinctive shape that remained practically unchanged through hundreds of millions of years of evolution. Nonetheless, there are variations of this shape that vary between and within species. We attempt to explain these variations by examining the partial derivatives of the cost of transport of a generic shark with respect to buoyancy, span and chord of its pectoral fins, length, girth and body temperature. Our analysis predicts an intricate relation between these parameters, suggesting that ectothermic species residing in cooler temperatures must either have longer pectoral fins and/or be more buoyant in order to maintain swimming performance. It also suggests that, in general, the buoyancy must increase with size, and therefore, there must be ontogenetic changes within a species, with individuals getting more buoyant as they grow. Pelagic species seem to have near optimally sized fins (which minimize the cost of transport), but the majority of reef sharks could have reduced the cost of transport by increasing the size of their fins. The fact that they do not implies negative selection, probably owing to decreased manoeuvrability in confined spaces (e.g. foraging on a reef).

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