Science. 1988 Mar 11;239(4845):1291-3. doi: 10.1126/science.239.4845.1291.
Diadromous migration, in which some fish species migrate from freshwater and feed in the ocean (anadromous species) and others migrate from the ocean and feed in freshwater (catadromous), has long been perplexing. However, when the distribution of diadromous species is examined with respect to global patterns in aquatic productivity, this apparent paradox is resolved. The contrasting directions of migration can largely be explained by the relative availability of food resources in ocean and freshwater habitats. Oceans are more productive than freshwaters in temperate latitudes, and anadromous species predominate. In contrast, catadromous species generally occur in tropical latitudes where freshwater productivity exceeds that of the ocean.
洄游迁徙，即一些鱼类从淡水进入海洋觅食（溯河洄游物种），而另一些鱼类则从海洋进入淡水觅食（降河洄游物种），这种现象长期以来一直令人费解。然而，当我们根据水生生产力的全球模式来研究洄游物种的分布时，这种明显的悖论就迎刃而解了。迁徙方向的差异在很大程度上可以用海洋和淡水生境中食物资源的相对可利用性来解释。在温带地区，海洋的生产力高于淡水，因此溯河洄游物种占主导地位。相比之下，降河洄游物种通常出现在淡水生产力超过海洋的热带地区。
