Spatial modeling of fish habitat suitability in Florida estuaries

Spatial habitat suitability index (HSI) models were developed by a group of collaborating scientists to predict species relative abundance distributions by life stage and season in Tampa Bay and Charlotte Harbor, Florida. Habitat layers and abundance-based suitability index (S,) values were derived from fishery-independent survey data and used with HSI models that employed geographic information systems. These analyses produced habitat suitability maps by life stage and season in the two estuaries for spotted seatrout (Cynoscion nebulosus), bay anchovy (Anchoa mitchilli), and pinfish (Lagodon rhomboides). To verify the reliability of the HSI models, mean catch rates (CPUEs) were plotted across four HSI zones. Analyses showed that fish densities increased from low to optimum zones for the majority of species life stages and seasons examined, particularly for Charlotte Harbor. A reciprocal transfer of S, values between estuaries was conducted to test whether HSI modeling can be used to predict species distributions in estuaries lacking fisheries-independent monitoring. The similarity of S, functions used with the HSI models accounts for the high similarity of predicted seasonal maps for juvenile pinfish and juvenile bay anchovy in each estuary. The dissimilarity of S, functions input into HSI models can account for why other species life stages had dissimilar predicted maps.