长江上游江津江段鱼类群落结构及资源利用

Community structure of fish and resources utilization in Jiangjin section of the upper Yangtze River

为了了解长江上游鱼类群落结构和资源利用现状，为物种和资源保护提供依据，对长江上游江津江段的渔业资源进行调查，对该江段的鱼类种类组成、优势种、渔业捕捞规格和单位捕捞努力量渔获量等进行分析．在长江上游江津江段共采集鱼类54种，隶属于3目9科35属，鲤形目和鲇形目鱼类占主体，约占总种数的96．3％；其中，长江上游特有鱼类共15种，占鱼类总种数的27．8％．渔获物分析表明，各渔具年度间渔获物组成差异不显著，圆口铜鱼、铜鱼、圆筒吻鲴、长鳍吻鲴、瓦氏黄颡鱼、中华沙鳅和福建纹胸跳等种类为优势种；大部分捕捞个体体重小于150g，体长小于200mm．该江段流刺网、小钩和百袋网的单位捕捞努力量渔获量分别为3．60～9．45、1．33—4．32、2．55～7．80kg／船／日．与历史资料相比，长江上游江津江段渔业资源已严重衰退，许多珍稀特有鱼类种群数量不多，渔业捕捞规格小型化趋势严重，单位捕捞努力量渔获量下降．该江段渔业资源处于过度利用状态，建议采取休渔和渔民转产转业等措施，加强物种和资源保护．

In order to understand the present status of community structure of fish and resources utilization in the upper reaches of the Yangtze River, and provide information for species and resources conservation, surveys on fishery resources in Jiangjin section were carried out. Species composition, dominant species, fishing size and catch per unit effort were analyzed. Altogether 54 fish species, 35 genera, 9 families and 3 orders were collected in Jiangjin section of the upper Yangtze River. Most of them belonged to Cypriniformes and Siluriformes, taking up 96.3% of the total species. Among these fishes, fifteen species were endemic to the upper reaches of the Yangtze River, accounting for 27.8% of the total species. The analysis of the catch showed that there was no significant difference on the catch composition of the same fishing gear among the different years, and Coreius guichenoti, C. helterodon, Rhinogobio cylindricus, R. ventralis, Pelteobagrus vachelli, Botia supercilliaris and Glyptothorax fukiensis were dominant species in Jiangjin section. Most of the individuals caught were smaller than 150 g in weight and 200 mm in length. The catch per unit effort of drift- trammel-net, baited hook and multi-codend-net was 3.60-9.45, 1.33-4.32 and 2.55- 7.80 kg per boat per day, respectively. Compared with the previous study data, the fishery resources in Jiangjin section declined seriously with low catch and small fishing size, and many rare and endemic species had small populations. The fishery resources in Jiangjin section have been over utilized, and measures such as fishing closures and fishing industrial transfer are suggested to be taken to improve the species and resources conservation.