Increases in Sarasota Bay boat traffic reflect the swelling coastal populations in both Sarasota and Manatee Counties. High levels of boat traffic can lead to injuries or disturbance to wildlife, as manifested by changes to behavior and acoustic signaling. While previous research conducted by SDRP has demonstrated short-term behavioral and acoustical responses of individual bottlenose dolphins to vessel traffic, this study aims to examine the relationship between boat use and dolphin use of Sarasota Bay. Additionally, yearly increases in Sarasota Bay vessel activity have created an underwater acoustic environment that is significantly different from even thirty years ago. This project seeks to examine how increases in vessel activity alter the acoustic environment of Sarasota Bay and what effects these changes might have on resident dolphins.

In June 2005, I began field work in Sarasota Bay with the assistance of three college interns. We conducted line-transect surveys to document both boat and dolphin sighting location and attribute information. The data collected for this portion of the project are currently being compiled into a Geographic Information System (GIS) to allow for spatial analysis of the sighting distributions. In addition to surveys, we used focal animal behavioral follows (an approach pioneered by Jeanne Altmann, of the Chicago Zoological Society) to collect behavioral data from individual dolphins relative to local boat densities. The behaviors and GPS recorded track lines of the focal follows are also being entered into the GIS to allow for formal analysis of habitat selection and behavioral state relative to boat densities. Comparisons will also be made using a five year historical dataset of dolphin sightings and boat use within Sarasota Bay collected by Sue Hofmann and her Earthwatch Institute volunteer teams. Underwater boat noise was recorded in a variety of habitat types throughout the bay using autonomous recorders and the recordings are being analyzed to plan for more detailed acoustic sampling of the bay next summer.

Data entry and analysis will continue this year and my preliminary results will allow me to refine my questions for the second field season, which begins in June of 2006. It is my hope that results from this project will aid conservation efforts directed towards coastal cetaceans in other regions of increased anthropogenic disturbance due to vessel activities. This work will form the basis of my graduate research as a Ph.D. student at the University of California, Santa Cruz. Support for this project has come from NOAA Fisheries, Earthwatch Institute, a GAANN Fellowship, and the UCSC Ocean Sciences Department.