MEPS 485:165-179 (2013)  -  DOI: https://doi.org/10.3354/meps10306

ABSTRACT: We herein describe a long-term (22 consecutive yr, 1990 to 2011) time series of recruitment surveys for a guild of coral-sheltering fishes at 7 to 12 sites along a 26 km section of the west coast of Hawaii Island. For arc-eye hawkfish, the numerically dominant species, recruitment (defined as the contribution of young-of-year to the benthic population within several months after settlement from the water column) varied 7-fold among years averaged over sites. Nonetheless, recruitment also differed spatially, with sites along the Kohala Peninsula comprising a high recruitment group. Spatial differences were persistent (some sites predictably low, others predictably high) and generally lacked demonstrable variation over time. Complementary empirical data suggested that post-settlement processes (predation, interspecific competition) also affected recruitment. A dispersal model combined with currents from an oceanic circulation model (Hybrid Coordinate Ocean Model, HYCOM) was used to simulate the spatial patterns of settlement by larvae released throughout the main Hawaiian Islands. These simulations generally agreed with observed spatial patterns of recruitment. Greater recruitment was also predicted near geomorphological features (headlands) on Hawaii Island most influenced by the flow of surface eddy currents generated by prevailing E-NE trade winds. Empirical data and simulations together suggest that the headlands of west Hawaii Island likely enhance recruitment by intercepting or concentrating larvae at greater rates, but that post-settlement processes dampen variations in settlement. We suggest that habitat geomorphology should be considered in the criteria used to select sites for no-take Marine Protected Areas at Hawaii Island.

KEY WORDS: Planktonic dispersal · Larval transport · Pre- vs. post-settlement processes · Paracirrhites arcatus · Cirrhitidae · Headland · Currents · Hawaii Island