渤海鱼类群落结构的年际变化

摘要

基于2010年和2012–2014年每年8月渤海渔业资源底拖网调查数据,根据优势种、单位个体重、相对资源量、Jaccard种类组成相似性系数和群落结构数量生物量曲线等指标,研究渤海鱼类群落结构的年际变化,结果显示:(1)2010年和2012–2013年,总鱼类和底层鱼类种类数一直呈下降趋势,2014年有所恢复;2010年和2012–2014年暖温种种类数基本上呈下降趋势;(2)底层鱼类优势种由小个体的虾虎鱼(Gobiinisp.)代替大个体的小黄鱼(Pseudosciaena polyactis),中上层鱼类优势种则由植食性为主的黄鲫(Setipinna taty)和斑(Konosirus punctatus)转向浮游动物食性的鳀(Engraulis japonicus);(3)2010年和2012–2014年渤海底层鱼类和总鱼类年间站位相对资源量两两间都不存在显著性差异(P>0.05),2013年与2014年间总鱼类及2014年与2010年底层鱼类年间站位相对资源量方差无显著性差异(P>0.05),其他年份两两间都为方差不齐(P<0.05),底层鱼类和总鱼类站位相对资源量年际存在极端异常值;(4)2010年和2012–2014年单位数量鱼体的个体重逐年下降,渤海鱼类这几年严重趋向小型化;(5)5种组内相似、组间相异贡献率高的鱼类种类,其年度相对资源量和分布变化较大;根据生物量与数量优势度曲线及W统计值判断,2010年渤海鱼类群落结构比较稳定,2012年相对稳定,2013年和2014年处于干扰状态,特别是2013年的鱼类群落结构处于比较严重的干扰状态.综上所述,渤海鱼类群落结构在2010年和2012–2014年发生了较大改变,处于受干扰不稳定状态.%We evaluated variations of in fish community structure in the Bohai Sea using data collected during trawl surveys in August 2010–2014. The dominant species, individual mean body weight, relative resource, Jac-card's similarity coefficient, an abundance biomass comparison curve and multivariate statistical analyses were used to evaluate the data. The results showed that the abundance of all fish species decreased from 2010 to 2013, the abundance of a few species increased in 2014, but the abundance of all warm-temperate species decreased from 2010 to 2014. The dominant fish species changed drastically from 2010 to 2014, and the dominant demersal fish species changed from Pseudosciaena polyactis to Gobiini sp., whereas the dominant pelagic fish species changed from Konosirus punctatus and Setipinna taty, which feed on phytoplankton, to Engraulis japonicus, which feed on zooplankton. No differences (P>0.05) among mean station resource were observed for any of the fish during 2010–2014, and the mean station resource data had hetero generous variances (P<0.05) during 2010–2014, except data of all fish between 2013 and 2014, and those of demersal fish between 2010 and 2014. The abundance biomass comparisons and statistical W values showed that the fish community was stable in 2010, relatively stable in 2012, but disturbed in 2014, and seriously disturbed in 2013.The annual relative resource and distribution of the five fish species with the highest contribution rate to similarity in the groups and differences between groups changed significantly. Mean weight of all fish decreased from 2010 to 2014, as the sizes of all fish in the Bohai Sea has tended to decrease in recent years. In conclusion, the fish community in the Bohai Sea changed dramatically from 2010 to 2014 and remains in a disturbed state.