A Preliminary Study on Biology of Main Commercial Fishes Surveyed From the Single Otter Trawl Fisheries in Zhoushan Fishing Ground Outside the Forbidden Fishing Line

On the basis of the single otter trawl fishery resources investigation in Zhoushan fishing ground outside the forbidden fishing line in eight and a half months(exclude the closed fishing season) of 2010,this paper analyzed the fishery biological characteristics of 7 main commercial fishes.Parameters,such as instantaneous rate of total mortality,instantaneous rate of natural mortality,fishing mortality and exploitation rates,were estimated using ELEFAN technique in software FiSATⅡ.The results showed that miniaturization was more apparent in most of the fishes compared with the historical records,and the instantaneous rate of total mortality increased.Among those fishes,5 species,whose exploitation rates were larger than 0.5,were high over exploited.The results indicated that miniaturization is serious in most of the main commercial fishes in Zhoushan fishing ground,and fishing greatly impacts on fisheries resources.Effective protection and management measures must be taken for the sustainable use of fisheries resources.