Abstract

Otolith-based reconstructions of daily larval growth increments were used to examine the effect of variation in larval growth on size and age at settlement and post-settlement growth, survival and habitat preferences of juvenile bicolor damselfish (Stegastes partitus Poey). During August 1992 and 1994, newly settled S. partitus were collected from Montastraea coral heads and Porites rubble piles in Tague Bay, St. Croix, U.S. Virgin Islands (17°45’ N, 64°42’ W). Daily lapillar otolith increments from each fish were counted and measured with Optimas image analysis software. S. partitus pelagic larval duration was 23.7 d in 1992 (n = 70) and 24.6 d in 1994 (n = 38) and larval age at settlement averaged 13.0 mm total length both years. Analysis of daily otolith increments demonstrated that variation in larval growth rates and size and age at settlement had no detectable effect on post-settlement survivorship but that larger larvae showed a preference for Montastraea coral at settlement. Late larval and early juvenile growth rates showed a significant positive relationship indicating that growth patterns established during the planktonic stage can span metamorphosis and continue into the benthic juvenile phase. Larval growth rates during the first two weeks post-hatching also had a strong effect on age to developmental competence (ability to undergo metamorphosis) in both 1992 and 1994 with the fastest growing larvae being 8 d younger and 0.8 mm smaller at settlement than the slowest growing larvae. These differential growth rates in early stage larvae established trajectories toward larval developmental competence and may prove important in biogeographical studies of larval dispersal.
Keywords: Larval to juvenile transition, otoliths, metamorphosis, Caribbean, Stegastes partitus