| Summary: | Marine mammals are ideal indicators of the health of the Salish Sea ecosystem. Monitoring of top predators such as the harbor porpoise (Phocoena phocoena) through individual photo-identification will provide critical information for marine conservation efforts. However due to their lack of overt markings, small size and evasive behavior, the harbor porpoise has often been overlooked in photo-ID studies. This study conducted primarily land-based photo-ID of harbor porpoises at Burrow’s Pass on the west side of Fidalgo Island, WA, where harbor porpoises are frequently observed, with some additional data from opportunistic transects of surrounding waters. Using a multi-feature identification strategy to categorize and group distinct markings, identification of individual harbor porpoises was found to be successful. Eight categories were identified (with 2-6 descriptors each): (i) Fin Shape, (ii) Fin Size, (iii) Fin Base Width, (iv) Fin Trailing Edge, (v) Peduncle, (vi) Scars/Lesions (left and/or right side), (vii) Pigmentation (left and/or right side), and (viii) Overall Coloration. Data collected since January 2014 revealed over 35 individuals successfully identified using this method, 28% of which have been re-sighted over days, weeks, months and between years. These results demonstrate that identification of individual harbor porpoises is possible, that the various marks used for identification are stable over time, and that there is some degree of site fidelity to the study area. To increase the scope of the work and involve the public, we collaborate with local citizens and local and transboundary research organizations who provide harbor porpoise photographs and sighting data from around the Salish Sea. Through a combination of dedicated research, local outreach and transboundary collaborations we are beginning to create a regional database of harbor porpoise ID, providing data that can reveal currently unknown aspects of this species’ sociality, behavior and life history.
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