We maintain three photo-ID catalogs that represent our different study areas: the 

 Sarasota Bay region, Charlotte Harbor, and Tampa Bay and the inshore waters of the 

 Gulf of Mexico. The catalog used for these analyses is a subset of a larger catalog 

 incorporating dolphins sighted outside of the limited Tampa Bay region considered 

 for this report. All catalogs are ultimately searched before an addition is made to the 

 appropriate catalog. 



The photo-ID catalog included 150 dolphins identified from the Tampa Bay 

 study area during 1975 through 1987 when the census was initiated in 1988. In 1993 

 we collaborated with Eckerd College (J. Reynolds, pers. comm.) in examination of a 

 portion of the photo-ID catalog established by B. Weigle (Weigle 1990). We made no 

 additions to our catalog, but found 94 matches to dolphins in our existing Tampa and 

 Sarasota catalogs. As of September 1994, there were 2,045 dolphins (1,749 distinctive 

 non-calves) in the DBRI photo-ID catalogs for all study areas, including Tampa Bay. 



Analysis of Photographs 



Photographic slides are labeled with information from the corresponding 

 sighting: date, film roll number, sighting number, and location code. Labeled slides 

 are filed chronologically in archival-quality storage pages in binders. Comments 

 from sighting data sheets are read for clues and additional information to assist in 

 identification of animals (for example, distinctive features noted in the field, or 

 features distinguishing between two similar animals). Each slide is examined using 

 a 15-power lupe eyepiece to find all distinctive dolphins. Slides are sorted by each 

 identifiable individual within a sighting and the best-quality slides of each animal 

 showing the distinctive features of the fin are selected to compare with the photo-ID 

 catalog. 



The most prominent feature of the fin is identified and the category that best 

 describes that feature is searched for a potential match. Matches are often made by 

 comparing the slide directly to the print in the catalog. However, with a close match 

 or to distinguish between fins with similar features, the original slide is used for 

 comparison. To verify a match between similar fins, both fins are projected using a 

 slide projector with a zoom lens and traced to line up distinguishing features. To 

 confirm long-term or difficult matches, three experienced photo-ID researchers 

 examine the potential matches and must vote unanimously on the final match. When 

 a match is made with a fin in our catalog, all slides are labeled with the dolphin's 

 unique 4-place code and its name, and the dolphin is scored as a positive 

 identification. 



When a match is not found in the first category searched, all other possible 

 categories are searched to account for dolphins that have multiple identifying 

 characteristics. The entire catalog is searched before a new animal is added to the 

 catalog. If we are confident the fin is reliably recognizable, the dolphin is given a 

 name that describes the most obvious feature of the fin and an original 4-place code 

 that abbreviates the name is selected. To be considered a catalog-quality image, a 

 new entry into the catalog must meet the following criteria: the entire fin, from the 

 anterior insertion to the posterior insertion of the dorsal fin and the trailing edge of 

 the fin must be visible, the image must be in focus and perpendicular to the 

 photographer, and, when available, both right and left side images of the fin are 

 selected for the catalog. The best-quality slide is labeled with the name, code and 

 catalog category that describes the most prominent feature of the fin. A print is 

 made and added to the print catalog and the original slide is filed alphabetically in 

 the slide catalog. 



