Title: Catch comparison analysis between conventional and modified shrimp twin trawl in Cuba

Type:
Final project
Year of publication:
2008
Publisher:
UNU-FTP
Place of publication:
Reykjavík
Number of pages:
22

Abstract

A shrimp trawl modified to reduce by-catch was analysed in terms of total catch and catch at length in the Santa Cruz del Sur shrimp fishery, Cuban South-eastern shelf. The modifications in the trawl design mainly focused on decreasing the vertical opening and increasing the horizontal opening together with the addition of a Fisheye by-catch reduction device in the upper part of the codend extension. A total of 99 comparative hauls during three cruises using  the twin trawl method were completed with the modified trawl and a conventional trawl. Finfish catches were significantly reduced using the modified trawl but neither the number of Lane Snappers below length at maturation nor by-catch other than finfish was reduced. A significant difference in length distributions of shrimps between the trawl types was observed for the first and the third cruises. The modified trawl caught less undersized and damaged shrimp than the traditional trawl and mean shrimp lengths were higher for the modified trawl. A logistic regression revealed a length dependent split in favour of the modified trawl, with shrimps larger than 10 cm being caught to a greater extent. These results in addition to the significant difference in number of shrimps suggest that the modified trawl has a more favourable size selection of shrimps than the traditional trawl. 

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