渤海鱼类群落优势种结构及其种间更替

渤海是中国专属的内陆型半封闭内海。随着沿海经济发展和人类对自然环境作用的日益加剧，海洋生态环境健康度和海洋生物多样性正经受着前所未有的胁迫和影响(Fausch et al.，1990； Ray et al.，1991)。就自然环境演变趋势而言，受全球变化与入海淡水径流量动态影响，无不制约着河口湾及近海环境的物理、化学和生物等若干过程(Dame et al.，1996；Drinkwater et al.，1994; McErlean et al.，1973)。然而，许多科学家和社会公众始终关注的并非该过程本身，而是此类过程作用的结果及其该系统生物生产力输出产品形式，即海洋生物资源数量和质量的变化状况及其趋势。“渤海生态系统动力学及其生物资源持续利用”项目的启动，可望对此进行针对性的调查研究。本文根据近年来渔业生态学现场调査资料，运用数理统计的方法研究渤海区高营养级鱼类群落优势种结构及其时空格局。主要包括:（1）鱼类群落优势种结构及其时序动态，即时间持续性；（2）优势种成分的可替代性及其对水域生物资源生产力持续性的影响；（3）优势种成分的营养与空间生态位对系统外扰动的响应。其目的在于探明海洋生物群落演替动态及其对人类可持续性开发利用的响应机制。

STRUCTURING DOMINANT COMPONENTS WITHIN FISH COMMUNITY IN BOHAI SEA SYSTEM

The composition and spatiotemporal dynamics of dominants within fish community in Bohai Sea system were analyzed using comprehensive data sampled in two 10-year towing periods, in order to determine the succession pattern of community and the responsive mechanism contributing to the sustainability of biological production. The 119 fish in the 1982-1985, dataset were comprised of 69 warm temperate species (57.98%), 34 warm water species (28.57%) and 16 cold temperate species (13.45%). Among these components, 31 species comprised to 53.834 thousand individuals per square kilometers in NED and 792.048 kg/km2 in BED, were determined as important fish judged by Pinaka''s IRI (Index of Relative Importance), which related to the number, biomass and occurrence frequency for each species in the first sample period. Half-mouth anchovies, Setipinna taty, Japanese herring, Engraulis japonicus, spot croaker, Collichthys nivealus, and small yellow croaker, Pseudosciaena polyactics, were among the 4 dominants. Seasonal trend was shown up a single cycle around the year and the persistence measured in ISTR (index of species turnover rates) was 0.6792 between seasons. Compared with two 10-year data by same gear, community diversity during 1992 and 2000, had decreased in some aspects, such as species number, NED, BED by 38.66%, 35.46% and 46.1%, respectively. Correspondingly, seasonal persistence also decreased to 0.5902, showing that sustainability of fisheries productivity in the system is characterized by tending toward short age, weaker ecotrophic dynamics and fast turnover rate in production.