Study Of Main Biology Character And Analysis Of Resource Status On The Harvodon Nehereus

In recent years, the resource of the traditional economic fishes declined seriouslybecause of the excess of fishing and the pollution of the environment. The proportion ofthe large captures reduced and the quality of the captures declined. The data of the spotinvestigation and the routine survey on the fishery resource in the East China Seaindicated the quantity of the resource of the Harpadon nehereus increased gradually andthe H. nehereus distributed abroad. The yield of the H. nehereus was in rising currentbecause its delicious in the area along the sea of the Zhejiang Province. the H. nehereusmainly distributed in the offing sea of the East China Sea, and the resource of it hadpotential exploitation, but the studies on the H. nehereus were little. Based on the fisheryresource survey date of bottom trawl in the East China and the routine fishery resourcemonitor date between2008and2009, the fishery biology characters of H. nehereus werestudied and The status of the resource were discussed.Firstly, the biology characters were studied. In the distributing area, the salinity wassteady and the temperature and the deep of the water were extensive The dominate forklength of the H. nehereus ranged from120mm to200mm, accounting for70.55%andthe average fork length was165.23mm. The dominate weight ranged from10g to20g,accounting for28.21%and the average weight was34.10g. The ratio of male to femalewas1.70:1, the flourishing period of the H. nehereus was from July to September. Thedominate feeding intensity was0except in July, and the results on feeding habits studyindicated the H. nehereus appeared in the stomach content with high frequency,nextwas the Chaeturichths stigntatias, then Leptochela gracilis. At present, the status offishery resource on H. nehereus was better, an the quantity of fishing was stabilizationso the resource exploitation was potential.Secondly, the stomach content of H. nehereus were collected. The results showedthat H. nehereus belonged to nektivorous fish, and there was serious phenomenon ofcannibalism. More species of prey were ingested by H. nehereus, the Chaeturichthsstigntatias, Leptochela gracilis and H. nehereus, were the dominant prey in spring, H.nehereus, B enthosema pterotum, Acetes chinensis in summer, H. nehereus, B. pterotum,Apogonichthys lineatus in autumn, and B. pterotum, Trichiurus japonicus, H. nehereusin w inter. Fish was the dominant prey, Euphausiacea, Sergestinae and Natantia were thesecondary prey. The feeding intensity of H. nehereus was47.26%, and the average full stomach coefficient was35.43%, which was the highest in autumn and lowest in spring,and the feeding intensity varied with season.Larstly, the stock resource was estameted, the results showed that the H. nehereusdistributed mostly in the outer sea area of Jiangsu Province and in the outer sea area ofChangjiang estuary. The average resource in the East Sea area was6587t, the averageresource mantissa was4.79×108ind. All the results showed that the resource staus of H.nehereus was better, with the stabilized capacity. Because of the season of spawn wasjust in the Summer Close Season, the resource was protected to a certainty, the resourcehad some potential if managed suitably.