STATUS OF FISH RESOURCES, HISTORICAL VARIATION AND FISHERIES MANAGEMENT STRATEGIES IN HONGZE LAKE

In other to develop fisheries management strategies and protect biodiversity, historical variation of fish resources were analyzed in Hongze Lake, the largest impounding lake along the East-Route of China's South-to-North Water Diversion Project, by comparing the current sampling(in autumn 2010 and summer 2011) with historical data.There were 88 fish species recorded in Hongze Lake since the 1960's, among which 63 species were found during this investigation [6 species were first recorded, namely Squalidus wolterdstorffi(Regan), Panacheilognathus imberbis(Gunther), Rhodeus fangi(Miao), Mugil cephalus Linnaeus, Siniperca kneri Garman, Rhinogobius cliffordpopei(Nichols)]. Comparing with historical recorded, limnicolus species increased from 59% to 78%, but potamophilous and river-sea migratory species decreased from 22% and 7% to 3% and 3% respectively. For the 25 species that were not found in this study, 17 species were potamophilous, accounting for 68% of the disappearing fishes. Small fishes of Carassius auratus, Pelteobagrus fulvidraco, Coilia nasus and Culterichthys erythropterus were considered as dominant species in current fish community according to their high values IRI(Index of Relative Importance) in catches from weir-nets and gill-nets, and larger commercial species all had low IRI except Cyprinus carpio. Fishery yield of Hongze Lake was 22 million kg in 2010—2011, with a high contribution(89.4%, 19.67 million kg) of small fish species(mainly C. nasus and C. auratus) to the total harvest. While four major Chinese carps(Mylopharyngodon piceus, Ctenopharyngodon idellus, Hypophthalmichthys molitrix and Aristichthy nobilis) and large carnivores species(e.g. Channa argus,Siniperca chuatsi, Silurus asotus, Culter alburnus) contributed only 4.4%(0.96 million kg) and 0.89% in total fishery yield respectively. We analyzed influences of disconnection between lake and river, over-fishing and habitat destruction on fish resources, proposed fisheries management strategies, and predicted potential responses of fish and fishery to the construction of the East-Route of South-to-North Water Diversion Project in the paper.