长江靖江段鲇形目鱼类的数量动态分析

Abundance Dynamic of Catfishes in Jingjiang Section of the Yangtze River

长江靖江段处于长江下游与河口段的交汇地带,在长江河口渔业资源养护中起着重要作用。为了解该区域鲇形目鱼类(Siluriformes)的资源动态,我们于2002~2015年间在靖江沿岸设置一座定置张网,每月定期收集2份或3份渔获样本进行分析。结果显示:14 a共采集渔获样本447份,渔获尾数为144 741尾,渔获量为934 728.9 g。种类共计121种,隶属于14目28科77属。其中鲇形目鱼类共有6 160尾、48 890.5 g,隶属于4科7属15种,占总渔获尾数的4.26%(重量占比5.23%)。光泽黄颡鱼(Pseudobagrus nitidus)、瓦氏黄颡鱼(Pelteobagrus vachellii)、黄颡鱼(Pelteobagrus fulvidraco)和粗唇鮠(Leiocassis crassilabris)等4种鲿科(Bagridae)分别占鲇形目尾数的72.71%、20.55%、3.18%和1.70%,是主要的优势种。14 a的单位捕捞努力量渔获量CPUEN结果显示,光泽黄颡鱼和黄颡鱼总体上呈逐年下降趋势,瓦氏黄颡鱼呈不规则的年际波动状态,而粗唇鮠则呈逐年上升趋势。14 a鲇形目鱼类总体的相对重要指数(IRI)结果显示,光泽黄颡鱼和瓦氏黄颡鱼为这一水域的常见种,黄颡鱼为一般种,粗唇鮠为少见种。研究还显示,光泽黄颡鱼和瓦氏黄颡鱼的优势体长组分别为4~6 cm和6~10 cm,仅长江靖江段沿岸平均每年即约有342.5万尾的光泽黄颡鱼和85.3万尾的瓦氏黄颡鱼被捕获,因此该江段是宝贵的苗种资源库。建议应降低捕捞强度,控制沿岸污水排放,减少岸线码头建设,保护河岸植被,以维持幼鱼栖息、觅食和育幼环境,保护渔业资源。

The Jingjiang section of the Yangtze River, situates at the junction of the lower Yangtze River and the estuary, is the location of the National Aquatic Germplasm Resource Reserve for Eriocheir sinensis and Siniperca chuatsi, and plays an important role in fishery resources conservation. In order to clarify the Catfishes resources changes in this section, fish samples were collected 2 or 3 times per month by stow nets between 2002 and 2015. There were 447 samples in total, which included 144 741 fish individuals for total weight of 934 728.9 grams. All fish samples were identified to 121 species, which belong to 77 genus, 28 families and 14 orders. In those samples, the Siluriformes fishes comprised 6 160 individuals, which belong to 4 families, 7 genera and 15 species, and accounted for 4.26% of all fish quantities （weight ratio 5.23% ）. Four bagrid fishes （Pseudobagrus nitidus, Pelteobagrus vachellii, Pelteobagrus fulvidraco, and Leiocassis crassilabris ） were the dominant Siluriformes species, and they accounted for 72.71%, 20.55%, 3.18% and 1.70% of total Siluriformes samples, respectively. The CPUEN analysis of the 14 years sampling showed that P. nitidus and P. fulvidraco declined year by year, whereas L. crassilabris increased in the period, and the biomass of P. vachellii biomasses changed irregularly. The relative importance index（IRI） analysis of the 14 years samples indicated that P. nitidus and P. vachellii were common species, P. fulvidraco for general species, L. crassilabris for rare species in the waters. This study also showed that dominant body length of P. nitidus and P. vachellii is only 4 - 6 cm and 6 - 10 era, respectively. An average of 3. 425 million juveniles of P. fulvidraco and 0. 853 million P. vacheUii are caught annually in the Jingjiang section. This study suggests that we should reduce fishing intensity, control coastal wastewater discharge, reduce shoreline construction and protect riparian vegetation for fish habitats to protect the fishery resources.