Connectivity through ontogeny: fish population linkages among mangrove and coral reef habitats

Most evidence for ontogenetic migration of fishes from mangroves to coral reefs has been based on cross-sectional studies of <2 yr duration that have not considered annual variability in recruitment. Taking a longitudinal approach of following cohorts over time, we evaluated evidence for mangrove-derived replenishment of 10 coral reef fishes by drawing on data from 2 concurrent fish monitoring efforts conducted in Biscayne National Park, Florida, USA, over the period 1999 to 2007. Annual indices of abundance were calculated for fish estimated to be age-0 to 4* in both habitats, and correlation analyses, with appropriate temporal lags, were performed. Statistically significant (p < 0.05; r(2) = 0.30 to 0.71) correlations between juvenile abundances in mangrove habitats and adult abundances on the reef tract 1 to 2 yr later emerged for 4 species: Abudefduf saxatilis, Lutjanus apodos, L. griseus, and Sphyraena barracuda. This is one of the few longitudinal studies that uses juvenile abundance indices to test mangrove reef ontogenetic connectivity. Our results have potential utility for nursery habitat assessment, marine reserve design, and for forecasting species-specific year-class strength on the reef, where most fishing is directed.