东营近海鲬鱼渔业生物学及资源丰度的季节变化

基于2010年春、夏、秋3个季节东营近海生物资源与环境调查资料,对东营近海鲬鱼群体渔业生物学特征及资源状况进行研究,同时分析其时空变化规律。结果表明:东营近海鲬鱼群体的优势体长组随着季节变化有所波动,优势体长组从大到小排序为春季>秋季>夏季,但是最大体长个体和最大体重个体均出现在夏季。渔获物中雌性个体数量多于雄性,夏季雌、雄比为1.25∶1,秋季雌、雄比为1.78∶1,性腺成熟度多集中在I期和II期,摄食等级以少量摄食为主,多集中于1级和2级。东营近海鲬鱼资源丰度的季节变化波动较大,且平均渔获率和平均尾数渔获率均处于较低水平,所获鲬鱼个体体长多分布在300mm以下,体重多集中于100g以下,群体呈现小型化趋势。此外,由于时空变化出现了夏季集中,春、秋季分散的规律,笔者推测东营近海鲬鱼群体可能为生殖洄游群体,东营近海存在鲬鱼的产卵场。研究结果为渤海鲬鱼资源可持续利用与保护提供了理论依据。

Fishery Biology and Resource Abundance of Platycephalus indicus in Coastal Water of Dongying

Based on the data collected from the resource survey at coastal water of Dongying in three seasons(Spring,Summer and Autumn) of 2010,the fishery biology,distribution variation and stock changes of Platycephalus indicus were studied and analyzed.The results showed that predominant body length had seasonal variation with an order of: Spring>Autumn>Summer.However,individuals which had the biggest body length and body weight were found in Summer.It was also found that female individuals outnumbered male individuals and individuals with the maturity stage Ⅰ and gonad were dominant in the population.The sex ratios are female: male=1.25∶1 in summer and female: male=1.78∶1 in autumn.Moreover,the feeding intensity of the fish was low in this study(mostly in grade 1 and grade 2).The data also showed that stock changed greatly within the three seasons and individuals of the population are under a trend of miniaturization.Body length and body weight of most individuals are under 300mm and 100 g.Additionally,with the results of biological study and the seasonal distribution variation of P.indicus,it could be conjectured that the P.indicus population in Dongying may belong to the large population which migrates in the Yellow Sea and Bohai Sea,and there should be a spawning ground in the coastal water of Dongying for the fish.Also,this conclusion could offer help to the fishery management of P.indicus.