汕尾甲湖湾附近海域鱼类结构季节变动研究

目的]探讨甲湖湾附近海域2016年4个季度鱼类群落结构和营养级指数季节变化。方法]以Pielou指数、Shannon-Winener指数和Margalef指数描述鱼类群落多样性特点。采用Pinkas的相对重要性指数(IRI)计算鱼类群落优势种的组成。运用ABC曲线法分析鱼类群落的季节变化。结果]各季节调查共计捕获鱼类83种,其中肉食性鱼类占84.34%,底层鱼类占59.04%,暖水性鱼类占75.90%。各季节间优势种变化较为明显。在时空分布上,生物量密度和尾数密度最高均出现在夏季,生物量和尾数密度四季总体上呈现北高南低、东高西低的分布趋势。多样性方面,夏、秋季鱼类种类组成相对较为丰富,冬季生物量优势度最高。2016年度平均营养级指数为3.427,秋季高营养级鱼类平均体质量最高。结论]甲湖湾海域鱼类以中、高级肉食性为主。鱼类年度平均营养级属于中级水平。海域渔业资源处于过度开发状态。

Research on Seasonal Variation of Fish Community Structure in Jiahu Bay,Shanwei

Objective]To study the community structure and seasonal change of trophic level of fish in the waters of Jiahu Bay in 2016. Method]Pielou index, Shannon-Winener index, and Margalef index were used to describe the fish diversity, and Pinkas' IRI index was used to describe the composition of dominant species.ABC curve method was used to analyze the seasonal variation of fish community.Re-sult]A total of 83 fish species were collected, and among those, the proportion of carnivorous fish, demersal fish, and tropical fish were 83.34%,59.04% and 75.90%,respectively.The dominant fish species changed with seasons obviously.For special and temporal distribu-tion, the maximal biomass and abundance appeared in summer, and there was a declining trend from north to south, and from east to west. Comparison of biodiversity, the composition of fish is more abundant in summer and autumn,and the highest dominance of biomass appeared in winter.During 2016, the average trophic level of four seasons was 3.427 of a intermediate level,and mean weight of high trophic level fish reached the peak in autumn.Conclusion]The feeding habit of fish was mainly intermediate and advanced carnivorous in Jiahu Bay.The yearly average trophic level of fish is in a intermediate level.The fishery resources is in a state of over exploitation.