Whitetip reef sharks in Malaysia are suffering from a mysterious flesh-eating disease that has manifested in the form of spots and lesions on their heads. Scientists believe climate change is to blame for their condition, according to a Reuters report.
Named after the distinctive white tip on their fins, whitetip reef sharks are greyish brown sharks, measuring about five feet in size. The species is considered among the most common sharks in the Indo-Pacific coral reefs — found from South Africa to Central America. At present, the International Union for Conservation of Nature has classified the species as “near threatened.”
Currently, experts have ruled out the possibility of human interactions being somehow responsible for the skin condition — since the area where the diseased whales were photographed is a “marine protected area,” where fishing is prohibited.
“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 senior marine biologist with Reef Guardian, a non-profit conservation group, told Reuters. Reportedly, there are no settlements or industries in the vicinity of the region either.
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The sighting of the diseased sharks in Malaysia also coincided with reports of coral bleaching in the region — and experts are inclined to believe it’s not a coincidence. Coral bleaching, or the whitening of corals, is caused by the warming of waters due to higher than the normal ocean temperatures.
“We cannot ignore that changes are happening there due to higher temperatures,” Mohamed Shariff Mohamed Din, a professor in aquatic veterinary studies with University Putra Malaysia, told the media, commenting on the skin disease in sharks, as well as the coinciding bleaching event.
Experts suspect the lesions on the sharks are the result of a fungal infection activated by warm temperatures, which further manifests in the form of ulcers. “They are caused by the Fusarium fungus. It is not a common disease as the fungus is an opportunistic pathogen that attacks weakened immunities,” Mohamed Din told the Malay Mail, explaining that “immunocompromised conditions can be brought about by changes in the environment such as temperature, salinity, pH, pollution, etc.”
Is is unclear, however, whether the infection can be fatal.
At present, scientists are attempting to secure samples from infected sharks to confirm the exact nature of the disease. “If we can get shark specimens, we will surely at least be able to find out the pathogenic cause of the lesions,” said Mabel Manjaji-Matsumoto, a senior lecturer with the Borneo Marine Research Institute of Universiti Malaysia Sabah, adding that her team is planning to collect samples required for a full scientific study on the subject in July.
