Photo-identification Studies

Rough-toothed dolphins often have good fins for photo-identification. NOAA Photo by 
        Jason Baker
Rough-toothed dolphins often have good fins for photo-identification. NOAA Photo by Jason Baker.

Long-term photo-identification studies provide insight into habitat use, movements, and life history characteristics of individual cetaceans. Some species of cetaceans have naturally occurring markings on their bodies, flukes, or dorsal fins. Photographic records of these scars, nicks, notches, or color patterns can be used to uniquely identify individuals. Photographs of cetaceans encountered during sighting surveys are archived and associated with other sighting data, e.g., sighting location, group size and structure, and behavior. Individual cetaceans can be tracked over time and between locations on the basis of their unique photo-IDs.

PIFSC cetacean scientists have been conducting photo-ID research throughout the Hawaiian Islands, at Palmyra Atoll, and around Guam and the Commonwealth of the Northern Mariana Islands. These long-term studies will help establish new stock boundaries for island-associated cetaceans in each region. Once photo catalogs are established they may also be used for evaluating abundance using mark-recpature techniques.

PIFSC cetacean scientists are active participants in the Pacific Islands Photo-Identification Network (PIPIN), a group of researchers from the Hawaiian Islands who are studying spinner dolphins and using photo-ID as a primary research tool. PIPIN is creating a collaborative photo-identification database of spinner dolphin populations within the Hawaiian Islands to study movements of dolphins between islands (if they occur), and to determine if dolphin populations differ from one island to the next. Results of the cooperative studies will help managers assess and resolve issues with human-dolphin interactions, e.g., impacts on spinner dolphins arising from "swim-with-the-dolphins" tourism operations.