Are rocky intertidal pools a nursery habitat for juvenile reef fish ? An investigation of the spatial and temporal abundance patterns of juvenile fishes utilizing basalt tidepools on the island of Oahu and a comparative growth analysis of the endemic Kuhlia xenura

Abstract

The abundance and community composition of post-settlement juvenile fishes occupying basalt tidepools on Oahu was examined to determine the importance of this habitat as a nursery area. Spatial and temporal patterns among pools and between sites indicate significant differences in juvenile fish assemblage between sites (Makapu'u and Ma'ili), though this pattern was not consistent across months. The relative nursery quality of tidepools was compared using otolith inferred growth rates of juvenile Kuhlia xenura collected from Makapu'u tidepools and an adjacent stream. Results indicate faster growth for juveniles (35-40mm total length) occupying tidepools, but this pattern was not evident for other size-classes sampled. Periodicity of spawning and recruitment for K. xenura were inferred from otoliths, and a pelagic larval duration of 32 days calculated. Results indicate tidepools are an important nursery area for numerous juvenile fish species on Oahu, especially K. xenura, and should be a priority for research and management.