Durban - Marine scientists are hoping to throw new light on the mysterious skin lesions found on a humpback whale off Ballito that resemble the raw and ugly sores seen on several whales in Australia and South America.
There have been similar reports from Australia over the past five years, while South American scientists believe the increasing number of lesions seen on whales and dolphins off that continent could be linked to increasing chemical and sewage pollution of the coastal environment.
Last week, while disentangling a young 7m humpback whale from shark nets at Ballito, KZN Sharks Board staff noticed that the animal was in poor condition and “covered in lesions”.
Mike Anderson-Reade, the board’s head of operations, said the lesions seemed to be linked to a skin infection and that when seen from the air, the whale resembled an albino because of the severe lesions.
According to a circular distributed by a local marine ecologist, the exact cause of the infection was not known, but members of the public were advised not to touch or eat the meat if any dead whales washed up on the coast with such lesions.
In Australia, the lesions seen on whales were described as ranging from open raw sores to scar tissue or complete loss of the outer skin.
SA Marine and Coastal Management scientist Mike Meyer said there had been at least three similar reports from Australia in recent years, but no tissue samples seemed to have been taken for analysis.
He said the lesions seen on the adolescent humpback whale at Ballito could be related to a viral or bacterial infection.
A tissue sample had been collected from the Ballito animal and it was hoped that RNA (rhybonucleic acid) and DNA evidence could be extracted from this.
Meyer said he was only aware of one other similar report of lesions on a whale off the Wild Coast.
“While it is a concern, there are not a large number of animals being seen with this off our coast,” he said.
Nevertheless, some scientists have expressed concern that the increasing number of skin lesions seen on whales and dolphins could be linked to polluted sea water close to the coastline.
In a research paper presented to an International Whaling Commission meeting in 2008, researcher Leonardo Flach reported that whitish, velvety lesions were found in seven percent of coastal dolphins sampled in Paracas Bay in Peru.
Christina Castro and fellow researchers at the Pacific Whale Foundation in Ecuador told the commission in 2011 that chronic fungal infections seen on humpback whales could be linked to sewage discharged into coastal waters.
Australian scientists say measles-like morbillivirus infections have been linked to recent mass strandings of dolphins and whales in several parts of the world. Symptoms of this virus include lesions on the skin, mouth, joints, or lungs.
The Mercury