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通过食物组成分析,并结合多年渔获量统计和环境监测资料,就太湖鲢、鳙鱼渔获量变化的原因及对环境的影响进行了分析。结果表明:在9~12月份期间,微囊藻约占鲢、鳙食物体积比的90%以上;鲢、鳙渔获量在1983~2004年期间波动在(1305.4±380.0)t,占鱼类总产量的(7.18±3.32)%,其中仅1984、1985年接近2000 t。在富营养化条件下,太湖鲢、鳙鱼主要摄食微囊藻。影响其产量变化的主要原因是苗种放养量不足、捕捞强度过高和富营养化提供了充足饵料。提高鲢、鳙放养量,不仅可以利用富营养化条件下的微囊藻饵料资源,而且可以抑制太湖蓝藻暴发。
Based on the analysis of food composition and the statistics of catches and environmental monitoring data for many years, the causes of the changes of the catch of silver carp and catfish in Taihu Lake and the impact on the environment were analyzed. The results showed that microcystin accounted for more than 90% of the volume of the diet of silver carp and bighead carp during the period from September to December. The catchs of silver carp and bighead carp fluctuated between (1305.4 ± 380.0) t in 1983 and 2004, The total output (7.18 ± 3.32)%, of which only 1984, 1985, nearly 2000 t. Under eutrophic conditions, Taihu silver carp and bighead carp mainly inhabit Microcystis. The main reason that affected the change of yield was the insufficient stocking of seedlings, the high fishing intensity and the eutrophication which provided sufficient feed. Increasing silver carp and bighead carp stocking not only can utilize the microalgae bait material under eutrophication but also can restrain the outbreak of blue alga in Taihu Lake.