Abstract
Photo-identification as the instrument for marine mammal population studies was first used in the 1970s. The animals were identified through sightings by comparing shapes, coloration, scars and nicks on their dorsal fins, tail flukes and body sides. Belugas lack both the contrasting coloring and prominent dorsal fins, and almost never show their tails. Therefore, identification is mostly based on dorsal ridge profile and individual marks on the body sides.1 Often, the latter are skin defects of different origin. This method has proved useful for long-term beluga whale population studies in the White and Okhotsk Seas.2,3 Other cetacean photo-id studies have used evaluation of skin lesions in photos to provide valuable information about the relative amounts of predation pressure, the case of diseases3,4 and human-caused traumatization.5 For beluga whales, major categories of marks include scars from predators or conspecifics, skin diseases,6 ship strike marks, and other of natural or anthropogenic origin. To facilitate the research and minimize identification errors, we have compiled a list of skin injuries of different etiology and the persistency of their presence on belugas. Different infection agents (viruses, bacteria, fungi) are suspected to cause skin diseases in belugas. Thus, skin lesions often reflect the health status of individual animals and population overall. Similar to other photo-id studies, we hope to help identify the sources of skin lesions found in photo-catalogs as a foundation to pursue additional research related to evaluation and conservation of different populations in Russia. By creating a catalog and classification of skin lesions, we also hope to help other species photo-id studies in identification of the causes of observed skin defects and health assessment of different cetacean populations.
Acknowledgements
The authors wish to thank all participants of "The White Whale Program" and Fishermen from Chkalov Island, Russian Geographic Society for financial support of this project.
References
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