黄海鳀鱼越冬洄游分布及其与物理环境的关系

Wintering migration and distribution of anchovy in the Yellow Sea and its relation to physical environment

依据2001～2003年间秋、冬季调查资料，对黄海鳀鱼的越冬洄游分布与环境因子的关系作了初步研究；利用一个以温、盐为参量的刻画海区物理环境对鳀鱼适合程度的指标（环境适合度），对环境因子在鳀鱼洄游分布中的作用做了初步的定量探讨。结果表明，鳀鱼的越冬洄游分布呈现出一种为温盐环境因子所“驱动”的态势；黄海冷水团和黄海暖流是其两个主要控制因素。秋季黄海冷水团决定着鳀鱼的洄游与分布，鳀鱼主要聚集于黄海冷水团的边缘、底层水温11～12℃等温线附近，冷水团边缘应是鳀鱼越冬洄游的主要路径。冬季黄海暖流决定了鳀鱼的越冬分布，鳀鱼主要密集于黄海暖流入侵所形成的暖水舌边缘、水温11～13℃等温线附近。物理环境适合度与鳀鱼的分布有着良好的匹配，适合度由低到高的负梯度方向决定了鳀鱼的越冬洄游路线，适合度高值区恰是越冬鳀鱼的密集区；表明适合度可作为一有效环境指标在预测鳀鱼密集区形成中发挥重要作用。

The wintering migration and distribution of anchovy in the Yellow Sea and its relation to environmental factors were investigated on the basis of the survey data in autumn and winter from 2001 to 2003. The effects of environment factors on the migration and distribution of anchovy were probed quantitatively by using environmental fitness. This index is used for depicting the degree of fitness of physical environment for wintering anchovy, with temperature and salinity being taken as input parameters. It was found that the wintering migration and distribution of anchovy tended to be ＂driven＂ by such environmental factors as water temperatureand salinity, the Yellow Sea cold water mass （YSCWM） and the Yellow Sea warm current （YSWC） being two main controlling factors. In autumn, YSCWM determines the wintering migration and distribution of anchovy. During this period, anchovy mainly congregates round the bottom-water isotherm of 11～12℃ in the marginal region of the YSCWM. The marginal region of the YSCWM seems to be the main wintering migration route of anchovy. In winter, however, YSWC decides the distribution of anchovy. At that time, anchovy mainly concentrates along the 11～13℃ isotherm in the marginal region of the warm water tongue formed by the intrusion of the YSWC. The physical environmental fitness matches very well with the distribution of anchovy. The negative gradient direction of the fitness determines the route of the wintering migration of anchovy, as the areas with highest fitness just coincide with the areas highest density of wintering anchovy. Evidently, the environmental fitness, as a valid en vironmental indicator, could play an important role in predicting the formation of concentration region for anchovy.