Scientists discover a ‘significant increase’ in skin lesions on the bodies of endangered killer whales

Scientists studying a vulnerable group of orcas in the Pacific northwest region of Canada and the United States have made a significant discovery regarding an increase in skin lesions on their bodies. This occurrence is suspected to be linked to a decline in the orcas’ immune systems’ ability to combat disease.

The research, titled “Epidemiology of skin changes in endangered Southern Resident killer whales (Orcinus orca),” was published in the scientific journal PLOS ONE. The study involved analyzing digital photographs of Southern Resident killer whales in the Salish Sea to examine skin changes and determine if they could serve as indicators of individual, pod, or population health.

The Center for Whale Research provided the researchers with photographs primarily used for whale identification purposes. These images encompassed nearly 20,000 sightings of individual whales in the Salish Sea, providing valuable data for remotely assessing the health of these endangered animals.

The researchers noted a significant increase in the prevalence of interconnected grey patches on the whales’ skin between 2004 and 2016. Although the underlying cause of this problem remains unknown, the study authors express concern about its implications.

The scientists hypothesize that the skin lesions may be caused by an infectious agent, as they have ruled out potential environmental factors like changes in water temperature or salinity.

Moreover, the study highlights that this situation could pose a significant additional threat to the already challenged southern resident killer whale population, which is facing various issues.

While the health significance of these skin lesions is not fully understood, their potential connection to declining body condition and weakened immune response in an endangered population is worrisome.

Researchers emphasize the importance of understanding the origin and development of these lesions to grasp the health implications of their increasing prevalence.

The research was led by wildlife veterinarian Joseph K Gaydos, the science director for the SeaDoc Society, a program affiliated with the School of Veterinary Medicine at the University of California, Davis.

Gaydos stated in media reports that they were unaware of the dramatic increase in the prevalence of these skin lesions before analyzing the data, emphasizing the need to identify the potential infectious agent responsible.