春季黄河口海域2种网具渔获物组成的比较分析

Comparative analysis on catch composition with two fishing gears at Yellow River estuary in spring

根据2007年5月在黄河口海域弓子网和小型单船底拖网渔业资源调查资料,分析了2种网具的渔获物种类组成,并分别计算了Sorensen相似性指数(SS)、种类丰富度指数(R)、Shannon-Wiener多样性指数(H′)、Pielou均匀度指数(J′)和相对重要性指数(index of relative importance,IRI)。弓子网和底拖网的SS指数为0.63,2种网具渔获物组成的相似性较差。弓子网和底拖网的R、H′、J′指数分别为3.61、2.28、0.64和3.55、2.40、0.72,底拖网渔获物多样性程度高于弓子网。分析结果表明,2种网具的单位功率渔获量(catch per uniteffort,CPUE)均不高,且存在选择性差和对幼体生物伤害严重的问题。

Based on the survey data obtained by beam trawl and single-boat bottom trawl at Yellow River estuary in May 2007, a com- parative study on the catch composition with two fishing gears was analyzed; indices of Sorensen similarity （SS） , species richness （R）, Shannon-Wiener diversity （H）, Pielou evenness （J＇） and index of relative importance （IRI） were calculated. The similarity of catch composition between beam trawl and bottom trawl was relatively small with a Sorensen similarity of 0. 63. Indices R, H＇ and J＇ of beam trawl were 3.61,2. 28, 0. 64 and those of bottom trawl were 3.55, 2. 40, 0. 72, respectively. The results showed that the diversity of bottom trawl was greater than that of beam trawl. It is suggested that the catch per unit effort of the two fishing gears was low with a poor selectivity, which would be greatly harmful to young individuals.