Estuarine Fish Populations among Red Mangrove Prop Roots of Small Overwash Islands

Previous estimates of fish density among the prop roots of the red mangrove,Rhizophora mangle, have varied widely, and assessment techniques used are often detrimental to the habitat. This study outlines a method for assessing estuarine fish densities among prop roots of overwash forests that greatly reduces the detrimental environmental effects of sampling in this habitat. Minnow seines were used to surround small overwash forests at high tide, such that fish were trapped in the nets as water receded. More fish species were present in the open water areas adjacent to mangrove stands than among the prop roots. Densities and distribution patterns of roots and hydrophysical characteristics measured at the overwash forests were not correlated with the density of fish inhabiting those sites. Fish density was correlated positively with species richness among small mangrove overwash forests. Similarity in species composition of fish assemblages was higher between prop root and open-water habitats sampled in this study than similar estuarine habitats examined previously. Estimates of fish density varied greatly between samples, however, suggesting high variability in habitat use among fish species inhabiting red mangrove overwash forests