An animal is occasionally "visually confirmed" in the field when it is 

 recognized because it was familiar to an observer and it was counted as a positive 

 identification for photo-analysis even though it may not have been documented 

 photographically. 



For photo-analysis, a calf or young-of-the-year is considered positively 

 identifiable only if it can be recognized because of distinctive features that make it 

 identifiable independent of its mother. A small animal that appears in all slides next 

 to a larger animal in the "calf position," (i.e., alongside and slightly behind the 

 presumed mother), is assumed to be a calf. If the calf is with an identifiable mother, 

 but the calf is not distinctive, it is not scored as a positive identification. 



In some cases it is possible to identify animals in a sighting that are not 

 sufficiently distinctive to make long-term matches, or appear distinctive but are 

 unidentifiable because the entire fin is not visible, photo coverage is incomplete, or 

 photo quality is substandard. Each of these dolphins is classified as an "other..." 

 with some reference to the most distinguishing feature. Although it is not 

 considered a positive identification, an "other..." dolphin is counted toward revision 

 of the group-size estimates. 



Fins that lack distinctive markings are considered "clean" but may also be used 

 in calculating or adjusting group size estimates. In some cases, "clean" fins may be 

 distinguished from one another within a sighting based on differences in fin shape. 

 This minimum count of "clean" fins is added to the positive identifications and 

 "other" fins to calculate the minimum, maximum and best group size estimates. Thus, 

 the minimum estimate is a minimum count of distinguishable fins within a sighting. 



A grading system that integrates recognizability, photographic quality, and 

 coverage is used to identify the quality of a given sighting: 



Grade- 1 - All dolphins in the group were photographed or otherwise positively 

 identified. All the animals in the best field estimate are accounted for as a) 

 confirmed positive identifications; or b) as individuals that can be distinguished 

 within a sighting from a high quality photograph but do not warrant status as a 

 'marked' dolphin in the catalog. 



Grade-2 - There are photographs of some dolphins with distinctive fins that may be 

 in the catalog, but because of the quality of photographs it is not possible to 

 make appropriate comparisons with the catalog and make a match or assign an 

 identification. 



Grade-3 - Photographic coverage is known to be incomplete, because all dolphins 

 were not approached for photographs, no photos were taken, film did not turn 

 out, sighting conditions were poor, etc. 



Data Processing 



Sighting data and results from photo-analysis are entered into the Dolphin 

 Biology Research Institute (DBRI) database. The database currently includes 8,192 

 sighting records from Sarasota Bay, Tampa Bay, Charlotte Harbor and the inshore 

 Gulf waters from 1975 to 1993. We use the FoxBase+/Mac Version 1.1 relational 

 database management system containing dBase programming language that permits 

 us to write specific programs to manipulate the database. A Macintosh Ilsi computer 

 is used for data entry and a Macintosh Centris 650 computer is used primarily for data 

 manipulations. 



