Friday, January 31, 2014

Catch-and-Release fishing for Sharks - Paper!

Nothing to be proud of - source.

Good stuff!

Remember those interminable debates - especially here?
Now that Austin has finally published his research, the verdict is unequivocal: targeting those Great Hammerheads is just simply wrong - especially in the case of land based fishing that requires subduing and wrestling in the Shark all the way to shore. Considering the documented post release mortality, there is no best practice here as even those Sharks that swim away seemingly unfazed are in grave danger of dying shortly thereafter.
Of course one cannot always chose what takes the bait - but the deliberate targeting of that species must stop immediately.

Or as Austin puts it,
This study may also suggest that relying on visual observations of post-release vitality could underestimate mortality and that these events could still occur in conservation zones that wholly restrict shark harvest (e.g. shark sanctuaries) and/or require release of threatened or protected species (e.g. regional/national prohibited species, endangered species list). 

For example, in January 2012, the state of Florida added 3 species of hammerhead sharks (great, scalloped [ Sphyrna lewini] , and smooth [ S. zygaena] ) to their prohibited species list, requiring individuals caught in state waters to be released. 
However, our results suggest that great hammerhead sharks are particularly vulnerable to fighting on a line with short fight times, even when sharks are observed swimming away vigorously post-release. Thus, potential conservation strategies to address these issues in great hammerhead sharks (in addition to restricting harvest) could include having fishers avoid peak or aggregation areas/times, use weak fishing line or hooks, or simply cut the line nearest the hook (without having to ‘fight’ the animal; Stokesbury et al. 2011).
Synopsis here, paper here.

And here's the usual nice video by Neil's lab.

PS: follow-up Q/A on the Shark Defenders blog here.

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