东莞内陆自然水域鱼类资源变动的调查与分析

Variations of the Fish Stocks in Inland Natural Waters of Dongguan

调查东莞内陆自然水域1982-1984和2005-2010年的鱼类资源。结果显示,1982-1984年,有鱼类151种,分隶17目44科,其中洄游性鱼类8种,河口性鱼类47种。纯淡水鱼类中,鲤形目67种,鲇形目14种,组成东莞纯淡水鱼类的主体,约占84.4%;河口鱼类中,鲈形目26种,与鲱、鲻形目组成东莞沿岸、三角洲水网咸淡水鱼类的主体,约占76.7%。鲤形目、鲈形目和鲇形目组成东莞内陆自然水域原生态鱼类的主体,约占鱼类总数的80.1%。2005-2010年的复查结果,仅存鱼类107种,分隶18目40科,其中原土著鱼类96种,隶属15目34科。近30年间,有2目10科56种土著鱼类消失,减少37.1%,生物多样性下降;外来入侵鱼类增多3目6科11种,从原先占有比例的2.6%增至14%。分析主要经济鱼类的生物学特征以及鱼类资源变动原因,探讨鱼类资源的利用、增殖和保护。

Dongguan lies to the east of Pearl River estuary and the lower reaches of Dongjiang River with inland water areas of 13 866 hm2. Based on the surveys of fishery resources conducted from 1982 to 1984, and from 2005 to 2010, there were 151 fish species from 17 families and 44 orders, including 8 species of migration fishes, 96 species of freshwater fishes and 47 species of estuary fishes. Among the fresh water fishes, there were 67 species of Cypriniformes, and 14 species of Siluriformes, which accounted for a considerable proportion of 84.4% and were once the dominant fresh water fish species in Dongguan. Among the estuary fishes, there were 26 species of Perciformes, which together with Clupeiformes and Mugiliformes formed the main part of the fish species along Dongguan water areas and Pearl River Delta, accounting for 76.7%. Whereas, the Cypriniformes, the Perciformes and the Siluriformes made up the majority of the natural fish species in Dongguan inland natural water areas, accounting for 80.1%. According to the second investigation from 2005 to 2010, only 107 species belonging to 18 families and 40 orders had survived, of which 96 wild species were from 15 families and 34 orders. For the last 30 years, 56 species of wild species belong to 2 families and 10 orders have disappeared with a decrease of 37.1%and the biological diversities have declined;11 alien species, belonging to 3 families and 6 orders have surged from 2.6%to 14%. Besides, a detailed description of the major commercial fishes will be Dongguan lies to the east of Pearl River estuary and the lower reaches of Dongjiang River with inland water areas of 13 866 hm2. Based on the surveys of fishery resources conducted from 1982 to 1984, and from 2005 to 2010, there were 151 fish species from 17 families and 44 orders, including 8 species of migration fishes, 96 species of freshwater fishes and 47 species of estuary fishes. Among the fresh water fishes, there were 67 species of Cypriniformes, and 14 species of Siluriformes, which accounted for a considerable proportion of 84.4% and were once the dominant fresh water fish species in Dongguan. Among the estuary fishes, there were 26 species of Perciformes, which together with Clupeiformes and Mugiliformes formed the main part of the fish species along Dongguan water areas and Pearl River Delta, accounting for 76.7%. Whereas, the Cypriniformes, the Perciformes and the Siluriformes made up the majority of the natural fish species in Dongguan inland natural water areas, accounting for 80.1%. According to the second investigation from 2005 to 2010, only 107 species belonging to 18 families and 40 orders had survived, of which 96 wild species were from 15 families and 34 orders. For the last 30 years, 56 species of wild species belong to 2 families and 10 orders have disappeared with a decrease of 37.1%and the biological diversities have declined;11 alien species, belonging to 3 families and 6 orders have surged from 2.6%to 14%. Besides, a detailed description of the major commercial fishes will be given, and a comparative analysis of the variations of fishery resources and the uses, the value-adding and the protection of the resources will be discussed.