An Analysis of Stomach Contents of California Tide Pool Fishes

Abstract

The alteration of sandy bottom and tidepools, the varying depths of water, and the character of the marine vegetation along a rocky shorelinc combine to produce diversified environments within relatively restricted areas. The fauna, both vertebrate and invertebrate, is correspondingly rich and varied, and adds to the ecological diversity. Under these conditions strong competition is expected, for each individual would exert some pressure, directly or indirectly, on its associates, especially in respect to food. One aspect of this complex relationship is the predator-prey relation between the fishes and invertebrates. The dependence of the fishes on the invertebrates may be one of the most important and effective factors determining the whole biotic relationship. The coexistence of various species of fishes may at the same time be determined by the degree of selective predation. The following observations are concerned with this complex subject of competition for food. They indicate that the different species of tidepool fishes feed selectively on the invertebrate prey and that only a small proportion of the invertebrate species are utilized.