Catchability tests for reducing discard of pre-marketable fish and shellfish on small beam trawler with large mesh codends in Suounada area of the Seto Inland Sea [Japan]
2007
Kimura, H.(Yamaguchi-ken. Fisheries Research Center, Nagato (Japan))
Catchability tests were carried out with the aim of reducing discard of pre-marketable fish and shellfish on small beam trawler with large mesh codends in Suounada area of the Seto Inland Sea. Whole fish and shellfish caught by the large mesh codends such as 25 mm, 30 mm, 37.5 mm in mesh side and 75 by 15 mm rectangular mesh were compared to those caught by the control codend of 12.5 mm in mesh side by the parallel haul method during the period between April 14, 2003 and July 1. All of the large mesh codends succeeded not only to select off pre-marketable fish and shellfish in the range from 1.9 to 13.0 % in number in comparison with the control, but also to increase the catch of marketable fish and shellfish in the range from 1.21 to 3.75 times more than the control in the daytime. Though in the nighttime, 75 by 15 mm rectangular mesh codend failed to maintain the same catch as the control codend and the selectivity rate was also not sufficient (25.9 %) because shrimps clogged the large mesh with starfishes and jellyfishes.
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