Dominance in Fishes: The Relation Between Environment and Abundance

Abstract

Changes in abundance of dominant species of fish were positively correlated with environmental factors that improved survival, and abundance of the subordinate species was negatively correlated with the same factors. When dominance changed, the responses of both the dominant and subordinate species also changed. Implicit in this inverse relation is the conclusion that the abundance of the subordinate depends on the density of the dominant species, and this hierarchy must be recognized in the interpretation of the correlations. Changes in dominance not only explained why the response of a species changed from positive to negative, but also why different stocks did not respond in the same way to temperature. The findings support the thesis that climatic factors can affect the abundance of a species but do not govern its absolute population density. The results have important implications for fishery management.