The Catch Amount of Mediterranean Horse Mackerel Trachurus mediterraneus (Steindachner 1868) 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 1868) with gillnets. This target species T.mediterraneus and significant amounts of non-target species are caught in these nets. So, the technical and structural characteristics of the gillnets for commercial fishermen were determined and the target and non-target species were evaluated in catching operations. The multifilament gillnet mesh sizes of 18 milimeters polyamid, twine thickness of 210d/2, hanging ratio of 0.33 and the total length of approximately 200 meters. Also, the guarding nets were added in gillnets. T.mediterraneus and 29 non-target species were caught. The total amount was determined as 397.8 kilograms (kg) and 9204 individuals (ind). The weight of T.mediterraneus was determined as 156.5 kg (39.3%) of the total weight. The number of T.mediterraneus was determined as 3997 ind (43.4%) of the total number of ind. While the catch per unit effort (CPUE) for T.mediterraneus was calculated at 0.026 kg/m.operation-1 and 0.7 ind/m.operation-1, the CPUE for the total amount was calculated at 0.066 kg/m.operation-1 and 1.5 ind/m.operation-1. The total economic value was calculated at 15814.4 Turkish Liras (TL), which 9390 TL (59.4%) from T.mediterraneus and 6424.4 TL (40.6%) from non-target species. 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. These results will contribute to the creation of management plans and fisheries management for species-specific fishing gears used in a region.