Catching Efficiency of Mediterranean horse mackerel Trachurus mediterraneus (Steindachner ۱۸۶۸) Gillnets in the Sea of Marmara

The small-scale fishermen in the coastal area of the Marmara Sea between April and June, when purse seine fishing is prohibited, caught the Mediterranean horse mackerel Trachurus mediterraneus (Steindachner ۱۸۶۸) with gillnets. This target species T. mediterraneus and significant amounts of non-target species are caught in these nets. For this purpose, the technical characteristics of the gillnets used by commercial fishermen in T. mediterraneus fishing in the Marmara Sea were determined and the target and non-target species caught in ۳۰ catching operations were evaluated. Some of the technical and structural features of the multifilament gillnets used in this study were determined as mesh sizes of ۱۸ mm PA, twine thickness of ۲ numbers, floating material PL with ۲ numbers, sinker material Pb with ۵۰ g, hanging ratio of ۰.۵۰ and the total length of approximately ۲۰۰ meters. T. mediterraneus and ۲۹ non-target species were caught during catching operations. The total amount was determined to be ۳۹۷.۸ kg and ۹۲۰۴ individuals. The weight of T. mediterraneus was determined to be ۱۵۶.۵ kg. This amount constitutes ۳۹.۳% of the total weight. The number of T. mediterraneus was determined to be ۳۹۹۷ individuals. This amount constitutes ۴۳.۴% of the total number of individuals. While the catch per unit effort (CPUE) for T. mediterraneus was calculated at ۰.۰۲۶ kg/m.operation-۱ and ۰.۷ individuals/m.operation-۱, the CPUE for the total amount was calculated at ۰.۰۶۶ kg/m.operation-۱ and ۱.۵ individuals/m.operation-۱. While targeting T. mediterraneus with gillnets, a total economic value was calculated at ۱۵۸۱۴.۴ Turkish Liras (TL), this was calculated at ۹۳۹۰ TL (۵۹.۴%) from T. mediterraneus and ۶۴۲۴.۴ TL (۴۰.۶%) from non-target species that are commercially evaluable. This study is important in terms of revealing for the first time the catch efficiency of gillnets used by commercial fishermen to catch T. mediterraneus in the coastal area of the Marmara Sea, which is an important fishing area. As a result, it is thought that the fishing gear used species-specific will contribute to the creation of management plans and fisheries management.

کلیدواژه ها:

Coastal area ، Target species ، Non-targeting species ، Fisheries management ، Economic value