Genetic Analyses of Stock Structure in Tampa Bay: Examining Community Structure of Bottlenose Dolphins in Tampa Bay using a Genetic Approach
By Kim Urian, M.Sc.,
University of North Carolina, Wilmington

In my Master’s thesis work I described five separate communities of dolphins in Tampa Bay, defined by their patterns of association and home ranges. We are now interested in determining how much gene flow occurs among these five communities and how well they fit the model described by Karen Martien and associates. In August 2003, we conducted field work in Tampa Bay to examine the genetic structure of these communities.

We conducted biopsy sampling and photo-identification surveys of dolphins throughout northern and western Tampa Bay from our field base in St. Petersburg. We focused on dolphins identified in previous surveys and, in particular, we targeted known members of specific communities. Genetic samples have already been collected from two communities in southern and eastern Tampa Bay as part of other SDRP projects, so we focused our efforts on the other three communities - including the waters of Old Tampa Bay and Hillsborough Bay. We saw many familiar fins from the surveys we conducted during 1988-1993, and collected 28 genetic samples from dolphins over the course of 9 field days. We obtained 13 samples from community 2, 4 from community 3 and 11 from community 5. Our success was due in large part to the skill of Brian Balmer, who conducted the biopsy sampling. And, as an added bonus, on August 20th, we saw FB58 and his partner, TNLV, east of McDill Air Force Base; FB58 is one of the first animals tagged by Randall Wells and Blair Irvine in 1970. This was the farthest point FB58 has been documented outside Sarasota.

The analysis of the digital images we obtained during the August surveys will be conducted this winter to determine the identities of the dolphins we sampled, and the biopsy samples have been provided to NOAA Fisheries for genetic analyses. Once the genetic analysis is conducted, we will be able to determine how much gene flow occurs among the five communities in Tampa Bay. This will help us to better understand the fine-scale population structure of bottlenose dolphins in this region. In addition, the samples collected during these surveys will supplement the growing genetic catalog of dolphins along the west coast of Florida and provide information on population structure over a broad geographic area. This research was supported by the NOAA Fisheries.