【摘要】 根据2000~2005年长江上游干流宜宾、巴南和万州3个江段三层流刺网的监测资料,分析了春禁前后3年渔获物结构和鱼类生物多样性的变化,对长江上游春禁效果进行了初步评价。春禁前后3年共监测到鱼类51种,隶属于3目18科(亚科)36属,以鲤科鱼类为主,占60.8%。春禁后,渔获物主要种类优势度有所下降,部分江段单位捕捞努力量渔获量表现出一定上升趋势,3个江段Margalef指数、Pielou指数和Wilhm改进指数有一定升高,表明种类丰富度有所提高,群落结构趋于复杂,春季禁渔有一定效果。春禁前后渔获物种类的波动,可能与这些种类种群数量少,难以采到有关;春禁后主要种类平均体长、体重仍表现出下降趋势,可能与过度捕捞及资源在短期内难以恢复有关。建议延长禁渔期、严格控制禁渔结束后的捕捞强度等措施来提高禁渔效果,并采取恢复江湖联系、保护重要渔业水域水质、实施水利工程生态调度等措施来配合春禁制度的实施。长江渔业资源的恢复和保护是一个长期而复杂的过程,对长江禁渔效果的准确评估还需要长期监测和深入研究。更多还原

【Abstract】 Changes of fishing structure and biodiversity before and after three years′ spring fishing off were analyzed and the effects of the spring fishing off were assessed preliminarily according the monitoring data by drift net in Yibin,Banan and Wanzhou reaches of the upper Yangtze River in 2000～2005.Altogether 51 fish species belonging to 36 genera,18 families(subfamilies) and 3 orders were collected,and Cyprinidae was the dominant,accounting for 60.8% of the total species.After three years′ spring fishing off,dominances of the main species decreased,CPUE of part reaches increased,and Margalef diverdity index,Pielou evenness index and Wilhm Modified Shannon-Wiener diversity index of the three reaches showed the rising tendency,which indicated the richness of species number and complication of community structure,and the positive ecological effects by the spring fishing off.The fluctuation of fish species before and after the spring fishing off might result from those species with small population size and difficulty to be caught.Furthermore,decreasing trend of average body length and body weight of the main species might be by reason of the pressure from overfishing and difficult restoration in a short period.It is suggested that longer fishing off period and controlled capture efforts after the spring fishing off season should be carried out in order to improve the effects of the spring fishing off,while other conservation measures such as reconnection of rive-lake,protection of water quality in important fishery areas and ecological operation of hydrological projects should be put into practice.Restoration and conservation of fishery resources in the Yangtze River is a complex project with a long period,and long-term monitoring and more studies in the future are needed for precision assessments on effects of the spring fishing off.更多还原