Abstract: The essential elements of a digital-based dorsal fin photo-identification program for dolphins are described and compared to more conventional film-based systems. The account begins with a description of digital-specific camera features, controls, and options, including sensor type, as well as image acquisition, resolution, compression, and storage. Detailed descriptions are given of how these digital-specific features are integrated with nondigital-specific features, such as autofocusing, shooting mode, metering, and telephoto lens specifications. The most compelling features of a digital-based system, especially when compared to film-based systems, are realized during the laboratory analysis of digital images (i.e., the processes of sorting, matching, and cataloging). During these laboratory phases of analysis, the most important system elements are the broad and powerful range of photographic image analysis, manipulation, and file management tools available in Adobe Photoshop Version 7.0 and the methods developed to integrate these tools into a system of dorsal fin analysis. This account concludes with a review of what the authors like most about the system and why, the process of transitioning from a film- to a digital-based system, and an analysis of the operational and acquisition costs of this digital dorsal fin photo-identification system.

Key Words: digital, photography, photo-identification, bottlenose dolphin, dorsal fin, Photoshop, film, Tursiops truncates

Document Type: Research article

DOI: 10.1578/AM.30.2.2004.209

Page Numbers: 209-219