Skinless 'Naked' Shark Found Thriving in the Mediterranean's Depths

In July 2019, a team of marine researchers made an unusual discovery in the Sea of Sardinia. They caught a blackmouth catshark with no skin and almost no teeth—yet the creature was alive and seemingly healthy. The findings, later published in the Journal of Fish Biology in 2021, have raised questions about how such extreme abnormalities could occur in the wild.

The shark was found at a depth of 1,640 feet near Cape Carbonara, off the southern coast of Sardinia. Unlike typical blackmouth catsharks, which have greyish-brown skin with intricate patterns, this one was mostly yellowish and smooth. Its epidermis, parts of its dermis, and its dermal denticles—small, tooth-like structures that protect the skin—were completely missing.

Despite these missing layers, the shark appeared in good condition. Inside its stomach, researchers found 14 whole creatures, suggesting it had swallowed prey without chewing. This was surprising, as the animal had almost no teeth left.

Scientists believe the lack of skin may have slowed the shark down, making it less efficient in the water. Yet it had clearly adapted, surviving in an environment where pollution and acidification are growing concerns. The cause of its condition remains unclear, with theories ranging from genetic defects to the effects of climate change or chemical contamination.

This is the first time such severe abnormalities have been recorded in a free-swimming shark. While the animal was healthy at the time of capture, little is known about the long-term impact of these traits on its species. Further research will be needed to understand whether pollution, genetics, or other factors played a role—and what it might mean for blackmouth catsharks in the Mediterranean.