The Distribution of Vertically Migrating Fishes Across the Central Equatorial Pacific

Abstract

AbstractMidwater trawl samples of vertically migrating fishes indicated four latitudinal faunal zones in the central equatorial Pacific between Hawaii and Tahiti. Boundaries of the northernmost and southernmost zones coincided with the boundaries between the equatorial and central water masses. The equatorial water mass was divided into two zones with distinctly different faunas. Of the 112 species considered, 20 occurred in all zones, and most of the remainder fell into one of six groups based upon pattern of occurrence or absence in each of the faunal zones. Correlation of faunal boundaries with oceanographic features in the study area and consideration of distributional data on the species in other areas indicate that differences in thermal structure, and consequent differences in productivity, between the major water masses could account for some barriers to distribution, but that differences in the intensity and vertical extent of the oxygen minimum layer constitute barriers both within and between w...