三峡工程对河口及邻近海域渔业影响的初步探讨

河口只是河流与海洋之间的一小部分水域,但对人类社会的发展和生物的进化起着重要的作用。它不仅是生物种群繁殖、育幼和栖息的场所,而且是溯河和降海鱼类洄游的必经之路,因此,河口对生物种群的繁衍延续和资源补充,以及保持生态平衡具有十分重要的意义。 然而,河口又是生态环境十分脆弱和敏感的水域,同时也是受人类干扰最为严重的区域。因此,河口的生态环境问题愈来愈引起人们的关注,其中包括长江三峡水库的兴建对长江口及其附近海域生态、环境的影响,特别是对位于河口两侧的我国著名两大渔场——舟山渔场和吕四渔场的影响问题。影响渔业资源的因子是多方面而且错综复杂的。本文主要通过长江径流的变化与环境因子变量的相关分析,并根据三峡水库不同蓄水方案,对河口近海渔业的影响问题进行初步探讨。

IMPACT OF THE THREE GORGES PROJECT ON THE FISHERY OF THE CHANGJIANG RIER ESTUARY AND ADJACENT WATERS

There is compelling evidence that river inflow results in considerable inputs of nutrients.It is shown that freshwater outflow to the sea is an important factor which links variations with biological productivity in coastal waters. The Changjiang River Estuary is the breeding and nursery areas for many organisms and it is also the only way of migration for anadromous and catedromous fishes. The estuary is a mixed zone of fresh and sea water,where the environmental factors are varied and complex in the form of seasonal perrodicity. The abiotic(salinity, temperature, runoff and nutrient salt, etc ) and biotic( primary productivity, phytoplankton, zooplankton and necton )environmental features in the Changjiang River Estuary have been shown in this paper. In one year, the values of factors reach the peak in summer and autumn, and lower in winter, pick up in spring. It is shown that there is obvious relationship between the Changjiang River runoff and environmental factors by regression analysis.