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Selectivity of conventional and alternative codend design for five fish species in the Aegean Sea
Author(s) -
Tokaç A.,
Özbilgin H.,
Kaykaç H.
Publication year - 2010
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/j.1439-0426.2009.01379.x
Subject(s) - merluccius merluccius , hake , fishery , demersal zone , trawling , fishing , biology , merluccius , horse mackerel , oceanography , fish <actinopterygii> , geology
Summary Currently, traditional Mediterranean trawls are generally made with non‐selective netting and the fishing boats are involved in multi‐species fisheries. As a result, most near‐shore stocks are over‐exploited. Weather permitting, the demersal trawl fleet tends to fish in relatively deeper, international waters of the Aegean Sea, where the catch is usually higher. Therefore, the need for evaluation of the codends used in this fishery and the potential improvements to their selectivity are of prime importance. In the present study, selectivity data were collected for hake ( Merluccius merluccius ), blue whiting ( Micromesistius poutassou ), greater forkbeard ( Phycis blennoides ), blackbelly rosefish ( Helicolenus dactylopterus dactylopterus ) and fourspotted megrim ( Lepidorhombus boscii ) in commercial (300 MC) and square mesh top panel (SMTPC) codends. Trawling was carried out at depths of 274–426 m onboard a commercial vessel chartered for a 15‐day sea trial in August 2004. Selection parameters were obtained by fitting a logistic equation using a maximum likelihood method. Results of the selectivity analysis indicated that the commercially used 40 mm nominal mesh size PE codend was rather unselective for the species investigated in this study. In general, the square mesh top panel codend has relatively higher L 50 values than the commercial codend. However, except for blue whiting, even this codend is rather unselective when 50% maturity lengths (L M50 ) are considered.