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Mid-Atlantic Bottlenose
Dolphin Catalog |
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Susan Barco Dr. Marthajane Caldwell Dr. Cara Gubbins Larry Hansen Gretchen Lovewell NMFS-Beaufort Lab Fran Lapolla Rich Mallon-Day Dr. John Morris Dr. Ric Petricig
Dr. Andy Read Keith Rittmaster George Rountree Dr. Laela Sayigh Peggy Sloan Todd Speakman Dr. Rob Young |
In 1997 the U.S. National Marine Fisheries Service (NMFS) supported development of the Mid-Atlantic Bottlenose Dolphin Photo-identification Catalog (MABDC) to examine population structure of bottlenose dolphins along the western North Atlantic coast. The MABDC built on the existing collaborative efforts among individual researchers - particularly researchers from the North Carolina Maritime Museum, the Virginia Aquarium & Marine Science Center, and the Nags Head Dolphin Watch, who provided insight into the movement patterns of individual dolphins in VA and NC. The MABDC expanded these efforts to include the entire range of coastal dolphins along the southeastern Atlantic coast. Such a systematic, cooperative system was necessary because of the large range of some dolphins and the complex population structure in this region. The MABDC is modeled on methods developed by researchers who use individual identification to monitor wide-ranging populations, specifically the right whale and humpback whale catalogs. This catalog is also a cooperative program, comprised of images and data contributed by researchers conducting independent photo-ID studies from New Jersey to central Florida. The MABDC has grown from 461 identified dolphins from six contributors in May 1998, to include 4,014 dolphins contributed by 26 researchers or teams from 16 different field sites (multiple efforts exist at some sites), with images dating back to 1979. The curator (Kim Urian) selected the best dorsal fin image to be included as the ‘type specimen' of each dolphin; all images were evaluated for quality and “distinctiveness” the of dorsal fin, archived digitally, and incorporated into a relational database with associated field data. All images included in the MABDC have been processed for use with Finscan© , a computer-assisted matching system developed by Dr. Gil Hillman and colleagues at the University of Texas Medical Branch and Texas A&M University. All preliminary matching was conducted by the curator of the MABDC to ensure quality control and consistency. Potential matches made by the curator were circulated to contributors for verification; to confirm a match between two sites, consensus among the contributors from both sites and the curator is required. The MABDC was initially designed to test the null hypothesis that a single "coastal migratory stock" of bottlenose dolphins exists from New Jersey to central Florida by identifying movement and residency patterns of individual dolphins. We used movements of dolphins among research sites, or the lack of movements, to test the null hypothesis, and to construct alternative hypotheses of population structure in this region. Results to date show that the patterns of movements of bottlenose dolphins along the mid-Atlantic coast are complex and the null hypothesis of a single stock has been rejected. No matches were identified between the most northern and southern sites, and there appears to be a high rate of exchange among the northern field sites, where dolphins occur only seasonally. Other areas of frequent exchange include Beaufort and Wilmington, NC, and in general, there appears to be less movement between southern field sites. Current federal management practices assume that stock structure of coastal bottlenose dolphins of the western North Atlantic consists of seven summer distribution management units and five or six winter distribution management units. The definition of these management units is based almost entirely on findings that were facilitated by the MABDC; this structure has been supported by other methods including telemetry and genetics. Now that the MABDC has evolved into a powerful tool, it can benefit researchers interested in understanding the movement patterns of dolphins not only in their study area, but also on a larger scale. The catalog provides an opportunity for contributors to collaborate on projects by serving as a centralized, and standardized 'clearing-house' of information. Future plans for the MABDC include development of a web- based version of the catalog to browse, match, and identify dolphins. If you are interested in more information about this project, please contact Kim Urian ( kurian@ec.rr.com ).
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Contributors