Experiments on the Cod-end Selectivity of Beach Seine Nets on the Turkish Coast of the Aegean Sea

Authors: ZAFER TOSUNOĞLU

Abstract: Beach seine nets are commonly used in Turkish coastal areas, especially the Aegean Sea, to catch fish commercially. However, it is known that these nets place excessive pressure on juvenile fish stocks. The aim of the present study was to examine the selection of fish species caught by a beach seine net with a 36 mm mesh size cod-end. In the experiments, the covered cod-end method was used to catch fish escaping from the cod-end. The selectivity of fish species which were caught in higher proportions in terms of both number and weight within the commercial catch composition was evaluated. Fifty percent retention lengths (/_{50}) were 13.43, 11.22 and 9.84 cm for red mullet (Mullus barbatus), common pandora (Pagellus erythrinus) and annular sea bream (Diplodus annularis), respectively. While the /_{50} values for the beach seine cod-end were higher than the minimum landing size for red mullet, lower /_{50} values were established for the other two species. Moreover, most beach seine fishermen attach a small mesh bag (13-21-24 mm mesh size) to the end of the cod-end to catch small sardines (papalina), anchovies, sardines and picarels legally. In this case there is no selectivity for the cod-end. Consequently, these results also support the prohibition of beach seine nets as a management tool.

Keywords: Beach seine net, cod-end selectivity, covered cod-end method, 50% retention length (/_{50})

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