Patterns of spatial and species abundance within the larval fish assemblage of the North Pacific central gyre during late summer

Abstract

The larval fish assemblage in the epipelagic zone of the North Pacific central gyre near Lat. 28°N, Long. 155°W during late summer was sampled with stratified opening/closing bongo nets. This assemblage exhibited recurring patterns of spatial and species distributions. Spatial patterns included species vertical distributions, co-occurrence and pathchiness; species patterns included species composition and abundance relations. Both types of patterns changed with depth, the most dramatic change occurring in relation to the bottom of the summer mixed layer. An examination of the physical and biological environments of the epipelagic zone with relation to the summertime species and spatial patterns and to seasonal changes in larval fish species structure indicates that the thermal structure of the upper water column may exert a major influence on overall ichtyoplanton species and spatial structures within the gyre.