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Aquatic Productivity and the Evolution of Diadromous Fish Migration
Mart R. Gross, Ronald M. Coleman and Robert M. McDowall
New Series, Vol. 239, No. 4845 (Mar. 11, 1988), pp. 1291-1293
Published by: American Association for the Advancement of Science
Stable URL: http://www.jstor.org/stable/1700892
Page Count: 3
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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.
Science © 1988 American Association for the Advancement of Science