New codend designs to improve the size selectivity of fyke net for narrow-clawed crayfish (<i>Pontastacus leptodactylus</i>)

نویسندگان

چکیده

The narrow-clawed crayfish ( Pontastacus leptodactylus ) is one of the most ecologically and economically important freshwater species in Turkey. However, harvest this has declined from 7937 t 1984 to 696 2019. One primary reasons for decrease stock use fishing gears with poor size selectivity. In study, new codend designs were investigated improve selectivity fyke nets P. . Seven codends three different tested: (1) a commercially used standard 34 mm mesh Com34 ); (2) sorting grids 20 SG20 ), 25 SG25 30 SG30 bar spacing attached last circle net; (3) stiff rigged net, part (codend) SRN34 42 SRN42 50 SRN50 size. average length at 50% retention probability L selection range SR 75 – values 9.4 cm 3.1 cm, respectively. For , grids, 11.3 11.6 12.0 while 1.4 1.3 0.6 codends, 10.9 2.1 2.1cm 1.1 Overall, commercial resulted lower when minimum conservation reference 10 was considered. all tested showed improved compared standard, optimum results obtained grid decreased discarding by 15.7% classic thus, very result sustainability natural stocks.

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ژورنال

عنوان ژورنال: Aquatic Living Resources

سال: 2022

ISSN: ['1765-2952', '0990-7440']

DOI: https://doi.org/10.1051/alr/2022014