A close-up of the shark. Live Science
A rare discovery has been made off the coast of Albania: a ghostly white deep-sea shark. The critically endangered angular roughshark, known scientifically as Oxynotus centrina, was caught by a commercial trawler near Sazan Island, an uninhabited military base. The shark was found at a depth of approximately 656 feet (200 meters). What makes this particular shark remarkable is that it exhibits leucism, a rare genetic disorder that affects pigmentation.
Unlike albinism, which leads to a complete lack of melanin and often gives animals red eyes, leucism only partially disrupts melanin production. This results in pale or white patches on the body but leaves the eyes with normal pigmentation. According to Andrej Gajić, the lead author of the study and director of Sharklab ADRIA in Albania, this shark had pale skin with whitish-gray patches on its tail but otherwise normal eye pigmentation. Gajić confirmed that this is the first case of leucism documented in angular rough sharks and within their entire family, Oxynotidae.
Typically, angular roughsharks are dark gray, brown, or black, with spots on their head and sides that help them blend into their deep-sea environment. The pale appearance of this individual makes it stand out from others of its kind. While it’s unusual, Gajić pointed out that this lack of pigmentation likely does not significantly affect the shark’s ability to survive in the wild. In fact, studies have suggested that while leucistic sharks may be more visible to both predators and prey, this doesn’t seem to reduce their ability to feed, reproduce, or avoid danger.
Scientist Andrej Gajić is seen holding the shark underwater. Live Science
Cases of pigment disorders in sharks are extremely rare. According to Gajić, there have only been 15 documented instances of these disorders among deep-sea species. Leucism is typically genetic, caused by mutations that disrupt melanin production or distribution in the body. However, there are other possible causes for these changes in color, including exposure to pollutants, increased temperatures, hormonal shifts, and even inbreeding among isolated populations.
The team that studied the shark is particularly interested in how human activities, such as pollution and overfishing, might contribute to the appearance of such disorders in marine species. As deep-sea ecosystems face increasing threats, research into these abnormalities may help scientists understand how environmental changes are affecting marine life.
A comparison of the skin from a typical brown angular roughshark and the leucistic shark. Live Science
Vlorë, the region where the shark was discovered, might be an essential area for the conservation of sharks and rays. The waters around this area are home to several other critically endangered species, including little gulper sharks and spiny butterfly rays, which have not been recorded in the Adriatic Sea for over a century.
