长江中上游四大家鱼资源监测与渔业管理

根据1994～2001年的监测结果， 结合历史资料对长江中上游四大家鱼资源现状进行了分析。结果表明：(1)长江中上游四大家鱼在渔获物中的比列呈下降趋势；(2)四大家鱼群体结构中低龄鱼比重上升，高龄鱼比重下降；(3)1997～2001年监利江段四大家鱼鱼苗径流量分别为35.87亿尾、27.47亿尾、21.54亿尾、28.54亿尾和19.04亿尾，与1981年该江段67亿尾相比，分别下降46.5%、59.0%、67.9%、57.4%、71.6%。针对影响长江四大家鱼资源的主要因素，提出了保护长江四大家鱼繁殖和栖息地，保持天然水域的相对稳定，降低长江四大家鱼捕捞强度，加强渔政管理等一系列保护长江四大家鱼的措施。

MONITORING OF THE FOUR FAMOUS CHINESE CARPS RESOURCES IN THE MIDDLE AND UPPER REACHES OF THE YANGTZE RIVER

The four famous Chinese carps, i.e, the black carp (Mylopharyngodon), the grass carp (Ctenopharyngodon.idellus), the silver carp (Hypophthalmichthys molitrix) and the big-head carp (Aristichthys nobilis) are the main species for freshwater fishery and aquaculture in China. According to the monitoring results from 1994 to 2001 and historical data, this paper deals with the analysis of the status of fishery resources of Chinese carps.The results obtained are: (1) The ratio of Chinese carps in fishery has droped in the middle and upper reaches of the Yangtze River; (2)The proportion of the low age groups of Chinese carps increased and the advanced age group decreased; (3) The runoff of fry of Chinese carps was 3.587 billion, 2.747 billion, 2.154 billion,2.864 billion, 1.904 billion in the Jianli Section of the Yangtze River from 1997 to 2001 respectively,when comparing with 6.700 billion in 1981, Base on the main influencial factors strategies to manage the four famous Chinese carps resources were proposed, such as protecting spawning grounds, preserving relatively stablization of natural waters, enhancing fishery management, building the carps releasing stations,establishment the managment system of germplasm resources in the Yangtze River.