辽东湾不同型刺网捕捞性能的比较

为了提高近海渔业资源养护型捕捞与管理技术,促进《全国海洋捕捞渔具目录》的实施,2014年10-11月在辽东湾进行了网目尺寸为40 mm、50 mm、60 mm的单片刺网、双重刺网和三重刺网以及生产对照网的选择性对比实验.结果显示,各种实验网的渔获种类数均在6-9种之间,优势种口虾蛄(Oratosquilla oratoria)的优势度随网目尺寸的增大而减小,但花鲈(Lateolabrax japonicas)的优势度随网目尺寸的增大而增大.同型试验网在不同网目尺寸条件下的渔获量有显著性差异,其中,60 mm试验网与40 mm同型试验网的单位捕捞努力量渔获量(CPUE)比较,单片刺网为800％,双重刺网为650％,三重刺网为500％;而异型试验网在网目尺寸相同条件下对渔获量的影响相对较小.试验网的组内渔获组成平均相似度分别为单片刺网59.24％,双重刺网62.63％,三重刺网66.51％;组间分别为71.44％、67.50％和70.58％;对组内和组间平均相似度贡献最高的种类均为口虾蛄和花鲈.随着网目尺寸的增大,各型试验网的渔获物幼鱼比例呈下降趋势.

Fishing Capacity Comparison of Different Types of Gillnet in the Liaodong Bay

In order to improve the fishing techniques and management level of offshore fishery resources, promote the implementation of National Marine Fishing Gear Catalog, selectivity among single gillnet (with the mesh sizes 40 mm, 50 mm, 60 mm), double gillnet, trammel gillnet and productive fishing gear (control group) was compared in the Liaodong Bay during October to November 2014. The results showed that the catch species of all experimental and productive fishing gear was between 6 and 9; the dominant species of experimental and productive fishing gear were Oratosquilla oratoria (dominance decreased with the increased mesh size) and Lateolabrax japonicas (dominance increased with the increased mesh size). There were significant differences on yields of the same type nets with different mesh size (P=0.0003, P=0.001, P=0.002), compared the CPUE of 60 mm with 40 mm, the single gillnet is 800%, the double gillnet is 650% and the trammel gillnet is 500%; but the influence on catch yields of the different type nets with same mesh size was relatively small. The average similarity of intra-group catch composition of the network was: single gillnet 59.24%, double gillnet 62.63%, and trammel gillnet 66.51%; Meanwhile, the average similarity of the inter-group was 71.44%, 67.50% and 70.58% respectively; The species which had the highest contribution to intra-group and inter-group average similarity were O. oratoria and L. japonicas. With the increasing of mesh size, the proportion of the catch the proportion of juvenile in the catch of all types of gillnets showed a decreasing trend.