EFFECTS OF NUTRITION-MEDIATED LARVAL CONDITION ON JUVENILE PERFORMANCE IN A MARINE MUSSEL

Abstract

The potential for long-lasting effects of larval experience on early juvenile stages is growing in recognition as an important aspect of the ecology of organisms with complex life cycles. For marine species, most studies of recruitment have focused on the numbers of settlers that arrive to a site, largely ignoring the potential variability in larval condition or quality and how such variability may influence the likelihood of recruitment success. In this study, I investigated the effect of larval nutritional history on early juvenile performance, and whether these effects are mediated by conditions in the juvenile habitat for the marine mussel Mytilus galloprovincialis. I raised larvae in the laboratory under different food concentrations. Larvae raised with the highest food concentrations were significantly larger in size at metamorphosis and had higher proportional lipid content at metamorphosis than those from lower food concentrations. Half of the newly metamorphosed juveniles were outplanted into intertidal and subtidal habitats for 2 wk. The other half were maintained in the laboratory at two different juvenile rations for up to 20 d. Juveniles raised with high larval food had higher juvenile growth rates and attained larger juvenile sizes than those from lower larval food in all cases. There was a significant positive relationship between size at metamorphosis and juvenile growth for juveniles maintained in the laboratory. Early juvenile growth rates did not change over time (between 10 and 20 d post-metamorphosis). Juveniles raised in higher juvenile rations had elevated growth rates and attained larger final sizes after 20 d than juveniles from low juvenile rations across all sizes at metamorphosis. For juveniles in the field, there was no effect of tidal height on growth for 2 wk post-metamorphosis. Field conditions were more favorable than laboratory conditions for juvenile growth, yet even these more favorable conditions did not compensate for the effects of larval nutritional history on early juvenile growth. Losses of juveniles from both the field and the laboratory were higher for those that had been raised in lower larval food conditions than for those that had been raised in higher larval food, suggesting that vulnerability to early juvenile mortality may also be affected by larval history.