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

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 6418% and migration fishes were very scaring. It indicated that the tendencyof small-sized fisheries and the lower yieldfish were obvious.Due to water engineeringwere 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 muchfishing pressure inLake Chaohu. Furthermore,eutrophication and lackof aquatic macrophytes were affected the communities of dominantedfishes inLake 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 inLake Chaohu,both biomanipulation and non-biomanipulation should be suggested in future.