Dolphin Photo Identification Explained
Individual bottlenose dolphins can be identified by their dorsal fins. But how exactly is that done? And why bother?
A new report published by NOAA, with SDRP staff members Brian Balmer and Randy Wells as co-authors, explores the use of photo identification as a tool for making abundance estimates of inshore populations of bottlenose dolphins.
Abundance estimates are critical for dolphin stock assessments along the Atlantic Coast and the Northern Gulf of Mexico, because they inform management policy decisions.
You can’t manage the conservation a dolphin population unless you know how many dolphins there are. Right?
Using results from repeated photographic surveys from boats, scientists can estimate abundance with calculations comparing the identifiable dolphins with unknown dolphins.
We pioneered the use these techniques in the SDRP in1975-6, and the process undergoes continuing refinement.
The NOAA report, from a workshop attended by marine mammal experts, statisticians, and population biologists, sought to develop agreement on best practices for fieldwork, photo processing and analytical practices for estimating abundance.
For more information the report is available for downloading as a pdf, or from NOAA.
Rosel, P.E., K.D. Mullin, L. Garrison, L. Schwacke, J. Adams, B. Balmer, P. Conn, M.J. Conroy, T. Eguchi, A. Gorgone, A. Hohn, M. Mazzoil, C. Schwartz, C. Sinclair, T. Speakman, K. Urian, N. Vollmer, P. Wade, R. Wells and E. Zolman. 2011. Photo-identification Capture-Mark-Recapture Techniques for Estimating Abundance of Bay, Sound and Estuary Populations of Bottlenose Dolphins along the U.S. East Coast and Gulf of Mexico: A Workshop Report. NOAA Technical Memorandum NMFS-SEFSC-621. 30 p.
