The production of fishery resources and the maximum sustained yield in the Min-zhong fishery in Taiwan Strait

In this paper, according to the theory of marine ecosystem trophic dynamic, based on the primary productivity data of the Min-zhong Taiwan Strait collected from the marine science surveys in the Taiwan Strait, by investigation of the species composition and structure of fishery resource, the content of organic carbon in phytoplankton, ecological efficiency, the trophic levels of the 61 main species, and measuring the content of organic carbon of the 58 main species. The trophic dynamic model and Cushing' model are used to estimate the productivity of fishery resources, the trophic dynamic model and surplus yield model are used to estimate the maximum sustained yield of fishery resources. The result shows that the potential productivity of fishery resources is calculated using trophic dynamic model and Cusing model to be 38.59104 and 43.68104 t, respectively. The maximum sustained yield (MSY) of fishery resources is calculated using Cadima model, Schaefer and Fox model to be 25.32104 , 23.96104 and 25.28104 t, respectively. The maximum sustained effort is calculated using Schaefer and Fox model to be 3 372 and 3 983 of standard trawl boats in Fujian. The annual catches have been among 27.0010104 ～40.01104 t since 1994, and the devoted fishing efforts are 3 897～5 976 of standard trawl boats in Fujian, which have exceeded the maximum sustained yield and the maximum sustained efforts for 11 years. The fishes's tructure of the main population is simplification, miniaturization and younger. The ecological parameters of utmost length (L) and utmost weight (W) are smaller, the growth curvature (K) is increasing, the inflexion of weight (tr) is ahead the schedule, the length of the first maturity is shorter, the fishing mortality coefficient and the ratio of exploitation are increasing, so the fishery resources decline rapidly. We must intensify the management of the fish resources, and take powerful measures to control the fishing effort and catches.