넙치(Paralichthys olivaceus) 자원관리를 위한 동해안 자망의 망목선택성 연구

Abstract

The aims of this study are to identify the current status of oliver flounder(Paralichthys olivaceus) gillnet fishing in the East Sea, and to investigate the net selectivity by mesh size, considering the ecological characteristics of oliver flounder for establishing the fisheries resources management plan. Survey was conducted on fishermen engaged in gillent fishery at Gajin Port, Goseong-gun, Gangwon-do. The study on maturity of oliver flounder was carried out, and a mesh size selectivity test was conducted by chartering a coastal gillnet fishing vessel, Suwon-ho (2.97 tons). Gears used for the test were manufactured in mesh sizes of 90 mm, 105 mm, 135 mm, and 150 mm. For the network selectivity analysis, the normal function, log-normal function, and bi-normal function based on the SELECT model were compared and analyzed with the selectivity curve and the Kitahara method, which expressed the selectivity curve as one Master Curve. In addition, the optimal mesh was estimated using a value representing 50% selection based on the catch-free length of oliver flounder. According the survey, the mesh size of the gillnet used for catching oliver flounder in the East Sea was different from 90 mm to 150 mm depending on the fishing season. The total length (TL) at % maturity of oliver flounder was estimated to be 43.0 cm (50%), 51.8 cm (75%) and 72.2 cm (97.5%) for female, and 31.0 cm (50%), 39.8 cm (75%) and 60.2 cm (97.5%) for male, respectively. The mesh selectivity was analyzed using the distribution of Total length by mesh size, and the bimodal normal function had the best fit in estimating the mesh selectivity curve based on the SELECT model. Titration mesh is 25% of individuals from each mesh selectivity curve. 50% and 75% selectable mesh sizes were calculated and compared, The net size at which 50% of the Minimum landing size (35 cm in TL) of oliver flounder was selected ranged from 102.0 to 133.6 mm, and was estimated to be 114.0 mm in the curve of the bi-normal function. In the future, these results will be used as basic data to establish plans for the efficient use and management of oliver flounder resources.