渤、黄、东海高营养层次重要生物资源种类的营养级研究

Study on Trophic Level of Important Resources Species at High Trophic Levels in the Bohai Sea,Yellow Sea and East China Sea

利用2000年和2001年2次大面调查所收集的11970个胃含物样品分析结果,计算了黄海和东海生态系统高营养层次35个重要生物资源种类的营养级,同时,结合对渤海和黄海39个种类营养级历史数据的修正,讨论研究了我国海洋高营养层次生物资源种类营养级的研究策略和计算方法。主要研究结果为:(1)渤海重要生物资源种类营养级的变化范围为3.12～4.9,黄海为3.2～4.9,东海为3.29～4.55。近年来各海域高营养层次的营养级呈下降趋势,如渤海从1959年的4.1下降到1998—1999年的3.4,黄海从1985—1986年的3.7下降到2000—2001年的3.4;(2)高营养层次营养级波动主要是由于群落种类组成变化及单种类营养级年间波动引起的,而单种类营养级年间波动又直接与群体个体变小以及摄食食物的低营养层次化有关。因此,高营养层次的营养级变化是认识海洋生态系统生物生产动态的重要指标,需要对其进行长期和系统的监测;(3)建议在今后的研究中,根据简化食物网的概念,对占生物量绝对多数的重要生物资源种类的营养级进行重点研究并采用国际通用的标准划分计算营养级。

cThe trophic levels of 35 important resources species at high trophic levels of the Yellow Sea and East China Sea ecosystems were calculated by analyzing 11970 stomach samples collected during two synoptic surveys in 2000 and 2001, and the revised trophic level data of 39 important species in the Bohai Sea and Yellow Sea were also used to discuss the research strategy and calculation method of trophic levels of resources species at high trophic levels in China seas. The main study results are as follows:(1) the trophic levels of important resources species in the Bohai Sea,Yellow Sea and East China Sea varied in the ranges 3.12 to 4.9, 3.2 to 4.9 and 3.29 to 4.55, respectively, and the trophic levels of resources species at high trophic levels in above sea areas in recent years were on the decline, for example, the trophic levels in the Bohai Sea decreased from 4.1 during 1985 to 1986 to 3.4 during 2000 to 2001, and those in the Yellow Sea decreased from 3.7 druing 1985 to 1986 to 3.4 during 2000 to 2001; 2 the fluctuation in trophic level of high trophic level species was caused mainly by the change in community species composition and the interannual variation in single species trophic level, and the latter was related directly to the colonial individuals getting smaller and the food trophic level getting lower. Therefore, the changes in trophic levels of high trophic level species are important indicator for understanding the bioproduction dynamics in marine ecosystem and the long-term and systematic monitoring on these changes are needed; 3 it is suggested that according to the simplified version of food web, the future study on the trophic level shall be focused on the important resources species accounting for overwhelming majority of biomass, and the international standard shall be used to divide and calculate the trophic level.