[MARMAM] New publication on assessing bycatch in trawl fisheries

Simon Allen S.Allen at murdoch.edu.au
Mon Jul 7 09:01:04 PDT 2014

Dear MarMam-ers,

We're pleased to disseminate more of our research into protected species bycatch in trawl fisheries with the following publication:

Jaiteh VF, Allen SJ, Meeuwig JJ & Loneragan NR 2014. Combining in-trawl video with observer coverage improves understanding of protected and vulnerable species bycatch in trawl fisheries. Marine and Freshwater Research 65: 1-8.

The abstract reads as follows:

Assessments of incidental wildlife mortality resulting from fishing rarely account for unobserved by-catch. We assessed by-catch of protected and vulnerable wildlife species in an Australian trawl fishery by comparing in-trawl video footage with data collected by an on-board observer. Data were obtained from 44 commercial trawls with two different by-catch reduction devices (BRDs). Eighty-six individuals from six major taxa (dolphins, sharks, rays, sea snakes, turtles and sygnathids) were documented from video analysis, including the endangered scalloped hammerhead shark (Sphyrna lewini) and the critically endangered green sawfish (Pristis zijsron). On the basis of the 2008–2009 fishing effort of 4149 trawls and scaling from these results, we estimated the annual catch of protected and vulnerable species (+/- 1 s.e.) at 8109 +/- 910 individuals. Only 34% of by-catch was expelled through the BRDs. Independent observer data for the 44 trawls showed that 77% of the landed by-catch from these taxa were dead when discarded. The results indicate that unaccounted by-catch in trawl fisheries can be substantial, and that current methods of recording by-catch on-board vessels are likely to underestimate total fishing mortality. We recommend gear modifications and their validation through dedicated observer coverage, combined with in-trawl video camera deployments to improve current approaches to by-catch mitigation.

You can access the article at: http://www.publish.csiro.au/paper/MF13130.htm or drop the Vanessa a line (vanessa.jaiteh at hotmail.com<mailto:vanessa.jaiteh at hotmail.com>) for the PDF.

Kind regards, Simon

Simon Allen
Research Associate
Murdoch University Cetacean Research Unit
School of Veterinary and Life Sciences
Murdoch University
WA 6150 Australia

ph: +61(8) 9360 2823
mob: +61(0) 416 083 653
email: S.Allen at murdoch.edu.au<mailto:S.Allen at murdoch.edu.au>
web: http://mucru.org/group-members/simon-allen/

"The opposite for courage is not cowardice, it is conformity. Even a dead fish can go with the flow" (Jim Hightower)
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