In Sipadan, mystery skin disease among sharks has scientists and divers baffled

Julia Chan
·3-min read
Underwater photographer and naturalist Jason Isley said that white patches first appeared on the sharks’ heads last year, with a marked deterioration in the past few months. — Pictures courtesy of Jason Isley
Underwater photographer and naturalist Jason Isley said that white patches first appeared on the sharks’ heads last year, with a marked deterioration in the past few months. — Pictures courtesy of Jason Isley

KOTA KINABALU, April 15 — Concern is growing among environmentalists over the wellbeing of the ubiquitous whitetip reef sharks of Sipadan island, as most, if not all, appear to be suffering from a serious skin condition.

Underwater photographer and naturalist Jason Isley, who recently dived on the island, said that white patches first appeared on the sharks’ heads last year, with a marked deterioration in the past few months.

“The sharks are in a bad way. They have all had these crazy white patches — maybe a fungus? — on top of their heads for the last year and now it looks like it is eating into their flesh,” he said.

Isley said that he noticed the patches on all the sharks he encountered during his recent dive trips.

“All of them... from small patches to crazy conditions. It’s impossible to say how many live around Sipadan. All the whitetips we have seen have the patches; maybe the ones deep down don’t.

“I’m told this started to happen at the start of 2020 when there was a very warm water spell at Sipadan and quite a bit of coral bleaching also occurred. It is looking more likely to be related to water temperature effect,” he said.

There has not been any data on the shark population on Sipadan but they easily number in the hundreds and are seen on every dive, at almost any depth.

Isley, who has been diving in Sipadan for decades, said that the sharks started to suffer the skin condition last year when water temperatures were at a high of 31 degrees Celsius.

A Sipadan-based dive operation had reported the discovery to Sabah Parks then.

“But then, there is little that can be done to treat them, short of catching them all and treating them,” he said.

Marine Research Foundation executive director Dr Nicholas Pilcher said it was hard to treat a disease that was so rare nobody can pinpoint what the problem is or its cause.

“These types of infections are rare and so remain largely unstudied. What is needed is to capture one and take a swab and get it analysed,” he said.

Isley said that he noticed the patches on all the sharks he encountered during his recent dive trips. — Pictures courtesy of Jason Isley
Isley said that he noticed the patches on all the sharks he encountered during his recent dive trips. — Pictures courtesy of Jason Isley

The disease was previously reported in the remote Galapagos islands where environmentalists suspected weather conditions had also affected other marine and terrestrial wildlife.

But Sipadan, about 45 minutes from the mainland of Semporna by boat, is about as far removed as the Galapagos islands in Ecuador, so Pilcher said human-derived runoff or pollution is unlikely to be the cause.

But any studies or observations on the long-term effects on the shark population would be hard due to the nature of marine wildlife.

“A challenge at sea is that we don’t see the same specimen every day. We wouldn’t know if one died. So it’s hard to determine the severity. If we saw lots of them, and it was persistent, then it may be worrying,” he said.

Dr Pilcher said the best course of action now would be to start studying the incident and learn as much as possible from it.

“My suggestion would be to monitor this regularly, with photos, to see if it is a major problem,” he said.

When contacted, Sabah Parks director Maklarin Lakim said that its researchers were aware of the situation and are investigating the incident after receiving reports about the sharks’ condition.

“Initial indications suggest it is a bacterial infection. Our researchers will have a discussion with UMS experts on collaborative shark research. We will raise this issue then,” he said.

Sipadan island, off the coast of Semporna, is known as a divers’ haven for turtles, schooling barracudas and bumphead parrotfish, among other species.

While still popular, the authorities have tried to regulate access by limiting the number of people allowed to dive in the vicinity.

Related Articles Giant ancient sharks had enormous babies that ate their siblings in the womb Study: Prehistoric mega-shark raised its young in nurseries Orcas blamed for disappearance of S. Africa great white sharks