While sharks can often be seen with open wounds in the wild, it is quite rare to see obvious signs of infection on them. Obviously, shark skin must harbour properties that prevent infection, so shark researchers set out to investigate the possible contribution of the sharks’ skin bacterial community to the ability to heal fast.
For the study, an international team led by researchers at KAUST's Red Sea Research Center collected a total of 88 mucus samples from the back and gill skins with lesions as well as from healthy skins of 44 wild-caught blacktip reef sharks caught in the wild around the Seychelles Islands.
Researchers sequenced the samples to identify the bacteria present in them, then compared the samples from the different sharks and tested them to detect changes in response to injuries.
The team's analysis revealed no difference between the bacterial communities on the injured skin on gills and the uninjured gills or backs. In other words, there was no evidence of infection around the wounds. "We were surprised not to find any substantial change in the skin bacterial communities," said Claudia Pogoreutz, the postdoctoral fellow who led the study.
There were differences discovered in sharks in different locations, Pogoreutz continued, noting it could be due to any number of factors.
“The differences in shark skin microbial communities may reflect differences in the ambient environment, such as temperature, population density, nutrient availability or pollution, but we cannot rule out the possibility that the changes could provide an adaptive benefit to the sharks,” Pogoreutz said. “There's still so much to learn with respect to shark skin-associated bacteria."