巢湖渔业资源现状及其对水体富营养化的响应研究

THE STATUS OF FISHERY RESOURCES OF LAKE CHAOHU AND ITS RESPONSE TO EUTROPHICATION

2002年至2004年期间,对巢湖鱼类资源进行调查,共发现鱼类54种,隶属16科、9目,主要以鲤科鱼类为主(35种),占64.8%,与20世纪80年代相比,鱼类种类数减少了40种,主要表现在洄游性种类急剧减少,甚至消失。渔业资源结构(渔获物)表现为以湖鲚、太湖新银鱼等小型鱼类为优势种类,在渔产量的比例不断上升,而大型鱼类(如翘嘴、鲤等)的种群结构趋于低龄化,产量呈下降趋势。结合已有的历史资料,分析巢湖渔业资源变化的影响因素,结果表明造成巢湖渔业资源结构变化受人为活动的影响主要表现在水利工程修建、过度捕捞和水体富营养化等方面。同时探讨近20年巢湖渔业捕捞产量与水体氮磷含量变化的相互关系发现,水体磷的含量变化显著影响巢湖渔业的捕捞产量。因此,合理利用巢湖渔业资源,需要减轻水体富营养化,控制捕捞强度和人为调整渔业结构使得巢湖渔业可持续发展。

From 2002--2004, investigations on fish communities were carried out in Lake Chaohu. According to historic data, the dynamic variation of fishery resources of Lake Chaohu was analyzed in recent 50 years. There are 54 fish species found, belong to 8 orders, 16 families,of which the fishes of Cyprinidae were 35 species and accounted for 64.8% and migration fishes were very scaring. It indicated that the tendency of small-sized fisheries and the lower yield fish were obvious. Due to water engineering were built in 1960s,most potsmodromous fishes decreased greatly by 40% of total fish yield before the built of dams to less than 10% in present study period. Another important factor is overfishing.9 folds of fishing boats and 5 folds of fishermen were found in 2002, which brought much fishing pressure in Lake Chaohu. Furthermore, eutrophication and lack of aquatic macrophytes were affected the communities of dominanted fishes in Lake Chaohu. Based on analyses of composition of fish catchments and relationship between fish yield and eutrophication, eutrophication control and sustainable development of fisheries of Lake Chaohu are put forward. In order to develop sustainable fisheries in Lake Chaohu, both biomanipulation and non-biomanipulation should be suggested in future.