黄海夏季不同取样网具渔获物组成比较分析

根据 2 0 0 0年夏季双拖渔船和“北斗”号专业调查船对应站位拖网调查资料 ,进行了两种不同取样网具情况下渔获物组成的比较分析 ,结果表明 :渔船的单位扫海面积渔获量、几种重要种类的长度范围、平均个体长度、5 0 %选择长度、重量计优势度均高于“北斗”号 ,而渔获种类数则少于“北斗”号 ,且两者种类组成相似性较低 ,仅为 0 .4 5 8;而且“北斗”号的底层、近底层鱼类和无脊椎类占总渔获量的比例高于渔船 ,这主要是由于渔具的选择作用造成的。结果说明应用渔船针对渔业生产进行的渔业资源监测 ,对带鱼、小黄鱼、鱼等重要生产种类是适合的 ,能够反映其资源量状况 ,但对群落结构、生物多样性等生态系统水平上的研究却存在着明显的不足

Comparative Analysis on Composition of Catches withDifferent Sampling Gears During Summer in the Yellow Sea

Based on the data collected from bottom trawl survey using fishing vessel which have 36 survey stations, and the trawl survey of corresponding stations by R/V "Beidou" conducted in August 2000, a comparative study on the composition of catches with different sampling gears were analyzed. The results showed that the mean catch per haul per swept area, length range of several economically important species, mean individual length and selective length at 50% in fishing vessel were higher than those in "Beidou", while the number of species in fishing vessel survey was less than that in "Beidou" and the similarity of composition of catches between fishing vessel and "Beidou" was as low as 0.458; furthermore the proportions of demersal fish and invertebrates of total catches in fishing vessel trawl were higher than those in "Beidou". All of the results were mainly due to the selection of gears and also indicate that fishery resources monitoring using fishing vessel for the purpose of production is appropriate for some commercially important species such as Japanese anchovy, hairtail, small yellow croaker and Spanish mackerel, which could reflect the resources status, however, when it was applied in the study of ecosystem like community structure and biodiversity, there were some obvious limits because of the lack of the data of some commercially unimportant species.