春季禁渔对常熟江段渔业群落结构及物种多样性影响的初步研究

以2000~2004年4~6月渔业资源动态监测资料为依据，分析研究了3年春季禁渔(2002~2004)对常熟江段渔业资源群落结构及物种多样性的影响。研究结果表明：4~6月间常熟江段出现的鱼、虾、蟹类渔获物共有11目、18科、46种；春禁后，该江段总CPUE（单位捕捞努力渔获量）显著增加；优势种更替不明显，历年以刀鲚、鲻鱼、长春鳊等经济鱼类为主；刀鲚CPUE有所回升，资源衰退受到遏制；小型鱼类、幼鱼在渔获物中的比例明显上升； Margalef物种丰富度指数、Wilhm改进指数呈明显上升趋势，均匀度指数J′、优势度数Dw在窄幅范围波动。春禁对常熟江段渔业资源保护的生态效果较明显，春禁后渔业资源群落种间结构得到一定程度的改善，生物多样性上升。

PRIMARY STUDY ON EFFECT OF SPRING-FISHING-BAN SEASON ON FISHERY COMMUNITY STRUCTURE AND BIODIVERSITY IN CHANGSHU SECTION OF THE YANGTZE RIVER

Based on fisheries dynamic monitoring data during April~June from 2000 to 2004,the paper analyzed the effect of spring-fishing-ban season on fishery community structure and species biodiversity in Changshu section of the Yangtze River.The results showed that fishes of 11 orders,18 families,and 46 species were represented in Changshu section of the Yangtze river.After the season,the total catch per unit effort(CPUE) increased sharply in the section;the dominant species were mainly commercial fishes such as Coilia ectenes,Mugil cephalus and Parabramis pekinensis and the annual change of dominant species was not obvious.The CPUE of Coilia ectenes had risen up and the trend of resource deterioration had been kept within limits.The caught rate of pint-sized and juvenile fish rose markedly.The Margalef's index and Wilhm's index had an evident tendency of rising,while McNaughton's index and Pielou's index waved slightly.The ecological effect of spring-fishing-ban season on the protection of fishery resources has been obvious: the interspecific structure of fishery resources has improved to some degree and the biodiversity ascended after fishing-ban season.