基于生计渔业调查的黄河口西南侧潮间带渔业生物多样性及其季节变化

Seasonal biodiversity of fishery resources by set net in the intertidal zone to the southwest of the Yellow River estuary

中文关键词: 渔业资源  生物多样性  须子网  潮间带  黄河口

英文关键词: Fishery resource  Biodiversity  Intertidal  Set net  Yellow River estuary

中文摘要:

      基于2020年黄河口须子网生计渔业和生物组成周年监测数据，开展黄河口潮间带渔业生物多样性及其季节变化研究，评价须子网生产对黄河口渔业资源补充的影响。结果显示，黄河口潮间带的渔业生物种类丰富，共鉴定记录61种生物，以鱼类和甲壳类居多。生物多样性和优势种组成均具有明显的月变化。多样性水平以夏季7―8月较高，秋季10―11月较低；5―9月、10―11月组群分别具有较高的种类组成相似度。各类群的数量组成中，4―7月螺类数量居多，8月螺类和鱼类数量居多，9月鱼类数量居多，10―11月蟹类数量居多。鱼类是各调查月渔获的优势类群，其中，花鲈(Lateolabrax maculatus)和 (Liza haematocheila)为各调查月都出现的优势种。个体大小–频数百分比分布显示，黄河口潮间带是小型渔业生物以及多种幼鱼分布的重要区域。4―9月，渔获物的主体均由个体重量< 2 g的生物组成(44%~82%)，鱼类以个体质量< 20 g为主，优势种类组成月更替明显。研究表明，开展须子网生计渔业调查和监测是采集黄河口沿岸咸、淡水交汇区潮间带包括鱼类补充群体在内的诸多渔业生物分布资料的有效途径。研究还表明，须子网渔业生产虽为黄河口沿岸当地传统的生计渔业，但其低选择性及在迁移通道的布设方式等易对渔业资源自然补充和增殖养护群体造成破坏，建议主管部门根据幼鱼种类组成和出现季节特征，重点在夏季和初秋季对该渔业的网目和布设区域进行相应管控。

英文摘要:

      The Yellow River estuary is one of the three largest estuaries along the coastal waters of China, along with the Yangtze and Pearl River estuaries. Its adjacent seawaters are rich in biological resources, with abundant fish habitat, spawning grounds, and migration channels in the Bohai Sea and the Yellow Sea. However, as the waters are too shallow for a survey ship, data was insufficient for research in the intertidal zone of the salt and freshwater interchange. Instead, by interviewing and analyzing the daily catches by the set net of the local fishermen, this study explored the fishery biodiversity in the intertidal zone of the Yellow River estuary from April to November 2020. Yellow River estuary is rich in fishery resources, especially small fishery organisms and fish recruitment stocks. There were monthly variations in the dominant species composition and biodiversity index. A total of 61 species were recorded, most of which were fish and crustaceans. The diversity, evenness, and species richness index increased in summer (July and August) and decreased in autumn (October and November). By cluster analysis of the species compositions, the surveyed months can be divided into two groups: May to September, and October to November. Lateolabrax maculatus and Liza haematocheila were the most common and dominant species in all surveyed months. The main contributors to the catch of each month were: snails from April to July, snails and fish in August, fish in September, and crabs from October to November. Catches by the set net were mainly composed of individuals with body mass <2 g from April to September. From body mass-frequency distributions, fish with body mass <10 g were the main contributors to total catches from April to September. The mean body mass of fish in all surveyed months was 13 g/ind.. The dominant fish species with body mass with <20 g were: Gobioidei in April; L. maculatus in May; Konosirus punctatus in June; Pennahia argentata, Gobioidei, and L. haematocheila in June to August; and Sardinella zunasi, Thrissa kammalensis, T. mystax, Sillago sihama, Tylosurus melanotus, Gobioidei, and L. haematocheila in September. From the above results, the local set net fishery survey proved to be an effective method of collecting fishery data in the intertidal zone and can be incorporated in studies considering the distribution of fishery resources and breeding grounds in the seawaters adjacent to estuaries. In addition, this study provided clear evidence that set net fishing practices could severely impact the natural recruitment and stock enhancement of fish resources due to the low selectivity of nets and the overlap with larval fish migration channels. The number of larval fish captured by the set net fishery was, roughly estimated, several times higher than the local enhancement released. To minimize the effects of net mesh size, considering the spatial-temporal distributions of fish larvae, set net fishing practices should be concentrated to summer and early autumn, though further research is required to comprehensively account for both the protection of fishery resources and livelihoods.