‘Eating into their flesh’: Reef sharks with skin disease may be the latest victim of climate change

a fish swimming under water: A white-tip reef shark with white spots and lesions lies on the seabed off the coast of Sipadan Island.

Divers in the waters off Malaysia’s Sipadan Island have long enjoyed getting a glimpse of turtles, manta rays and white-tip reef sharks nesting in reefs of the Celebes Sea. But more recently they’ve come across a much less picturesque sight: sharks with skin lesions on their heads.

“It looks like it is eating into their flesh,” Jason Isley, an underwater photographer who has taken shots of the diseased sharks, told Malaysian media.

So far, attempts to trap and treat the sharks don’t seem to have succeeded and a full scientific study is yet to be completed, according to Reuters. But at least one marine expert said that the lesions appeared to be ulcers from a fungal infection that has roots in warmer sea temperatures.

“Immunocompromised conditions can be brought about by changes in the environment such as temperature, salinity, pH, pollution etc.,” aquatic medicine specialist Mohamed Shariff Mohamed Din told the Malay Mail in April.

“In the Sipadan case, it is most likely due to the warm water spell that also caused bleaching of the corals,” he said, adding that the condition was treatable, although there was a chance it could result in death.

Local divers started spotting diseased sharks last year, according to local press reports, though it was only after a photo of an afflicted shark went viral on social media that authorities dispatched a team to try to capture the marine creatures for further study.

Sea surface temperatures around the tropical island clocked in at 29.5 degrees Celsius (85.1 degrees Fahrenheit) in May, or an increase of 1.8 degrees Fahrenheit since 1985, according to a recent analysis.

“We can almost certainly pin the warming ocean as having a role in what we are seeing with the sickly sharks in Sipadan,” Davies Austin Spiji, a marine biologist with nonprofit conservation group Reef Guardian, told Reuters.

Experts said that any infection is unlikely to be linked to man-made pollution as Sipadan is fairly far off the coast of Borneo, a large Southeast Asian island that is shared by Malaysia, Indonesia and Brunei. The Malaysian government has taken measures to protect the area’s ecosystem, including the relocation of numerous resorts off Sipadan and limiting the number of diving permits issued daily.

As recently as last year, Sipadan was hailed as a model of maritime conservation efforts. “Sipadan’s success lies in the management of the reef habitat for sharks, as well as the well-enforced no-fishing policy within the park boundaries,” Samantha Sherman, a researcher at Canada’s Simon Fraser University said.

‘Eating into their flesh’: Reef sharks with skin disease may be the latest victim of climate change