Geospatial Analysis and Comparison of Habitat Costs for Resident Sarasota Bay Bottlenose Dolphins (Tursiops truncatus)

Abstract

The Sarasota Dolphin Research Program (SDRP) studies a resident Florida bottlenose dolphin population that faces many threats from human activities. These dolphins concentrate in different areas seasonally, possibly in response to changes in the distribution of prey or predators. Movement from one location to another involves certain “costs” to the dolphins, which are defined in this project as the potential for negative environmental interactions (natural and anthropogenic). Using an updated habitat map for the SDRP study area and a geoprocessing model, a cost analysis was performed in order to compare the cost values of eight primary habitat types. Results indicated that Mangrove and Channel are the most costly, while Open Bay and Pass are the least costly. I hypothesized that dolphins will use habitats with lower costs more frequently than habitats with higher costs, but previous research and SDRP photographic survey data show that these dolphins frequently use dredged channels to move between areas, and at the population level they do not use any habitat type disproportionately to its availability.