The Effects of Netting Twine on Discard Rates of Commercial Red Mullet Gillnets in Izmir Bay

In this study, discard rates of the commercial red mullet (Mullus barbatus) gillnets, made from different netting twine; monofilament and multifilament were presented. The nets were set near the shore in which contains sea grasses (Posidonia oceanica) in İzmir Bay. These areas are sensitive habitats. During the fishing trials, totally 32 fish species have been caught, 21 of which were non-marketable. The rates of these non-marketable species are 77.8% and %22.8 for monofilament and multifilament gillnets respectively in number. The Serranidae and Labridae families were dominant in catch composition. The CPUE of the monofilament and multifilament gillnets for weight were calculated as 129.6±5.1 and 36.9±1.3 respectively. As a result, monofilament gillnets were caught more non-marketable species than multifilament gillnets (P<0.05; z=0.007). Because of the high rate of discard species, it's not advisable to use monofilament gillnets near the shore, in which contains sensitive habitats.