Skin disease on rise in endangered killer whale population

Scientists studying endangered southern resident killer whales say the population is experiencing a troubling rise in skin disease. While they don’t know what’s causing gray patches to appear on the whales’ skin, researchers say they worry the lesions could point to underlying health problems in the struggling population. 

“Before we looked at the data, we had no idea that the prevalence of these skin lesions were increasing so dramatically,” said Joseph K. Gaydos, science director for the SeaDoc Society, an organization based at the University of California, Davis’s School of Veterinary Medicine. “It’s worrisome.”  

In a study published in PLOS ONE, Gaydos and his team analyzed thousands of photos taken over more than a decade in the Salish Sea, off the coast of British Columbia and Washington state. The images revealed six different skin disease syndromes. While none was associated with mortality, researchers fear the lesions could complicate efforts to recover the population. 

After ruling out potential environmental factors, the biologists suspect an infectious agent is responsible. They believe the increased occurrence of lesions may reflect a decrease in the ability of the whales’ immune systems to combat disease. 

Only 75 southern resident killer whales (Orcinus orca) remain. 

Read the study here.