Interdecadal Change in Reef Fish Populations at French Frigate Shoals and MidwayAtoll, Northwestern Hawaiian Islands: Statistical Power in Retrospect

摘要

Reef fish faunas were compared between surveys conducted more than a decade apartat each of two isolated and nearly pristine oceanic atolls (French Frigate Shoals (FFS) and Midway Atoll) in the northwestern Hawaiian Islands. Species composition, assemblage structure (density rankings), and population densities were compared to test the hypothesis that reef fishes had declined during a period of lower oceanic productivity in the central North Pacific. Within each of two principal habitats (barrier and patch reefs) at each atoll, species composition and rank densities differed little between sampling periods. Densities, however, generally declined by about one-third for many numerically dominant species and for taxa pooled into functional categories (trophic levels, feeding guilds).