Data from: Epidemiology of skin changes in endangered Southern Resident killer whales

Photographic identification catalogs of individual killer whales (Orcinus
orca) over time provide a tool for remote health assessment. We
retrospectively examined digital photographs of Southern Resident killer
whales in the Salish Sea to characterize skin changes and to determine if
they could be an indicator of individual, pod, or population health. Using
photographs collected from 2004 through 2016 from 18,697 individual whale
sightings, we identified six lesions (cephalopod, erosions, gray patches,
gray targets, orange on gray, and pinpoint black discoloration). Of 141
whales that were alive at some point during the study, 99% had
photographic evidence of skin lesions. Using a multivariate model
including age, sex, pod, and matriline across time, the point prevalence
of the two most prevalent lesions, gray patches and gray targets, varied
between pods and between years and showed small differences between stage
classes. Despite minor differences, we document a strong increase in point
prevalence of both lesion types in all three pods from 2004 through 2016.
The health significance of this is not clear, but the possible
relationship between these lesions and decreasing body condition and
immunocompetence in an endangered, non-recovering population is a concern.
Understanding the etiology and pathogenesis of these lesions is important
to better understand the health significance of these skin changes that
are increasing in prevalence.