A commercial trawler reeled in a rough angular shark (Oxynotus centrina), near the military island of Sazan. An unusual face to face, since this fish is an endangered species. But the individual in question is even more singular: it is the first case of leucism ever recorded in the species.
A pioneering discovery of leucism in sharks
Very quickly, the meeting was the subject of a study published in the Journal of Fish Biology, last October 16. While this is the first and only report of leucism in rough angular sharks, it is also the only situation of pigmentary disorder within the family of Oxynotidae.
The specimen was defined as “particularly pale with almost whitish spots on the tail, but the eyes had normal retinal pigmentation” by Andrej Gajić. The description matches signs of leucism, an uncommon genetic abnormality that affects pigmentation.
Not to be confused with albinism, where the living being cannot generate any melanin. Leucism acts differently: “an individual can still produce melanin, but it is lacking in certain areas or throughout the body” according to Andrej Gajić, director of Sharklab ADRIA in Albania and main author of the study.
A rare but worrying phenomenon for marine biodiversity
The discovery of a shark with leucism is particularly significant for the scientific community. Although atypical among sharks, this anomaly raises questions about possible causes, such as environmental changes or the effects of pollution.
For Andrej Gajić, certain external elements create “disturbances during embryonic development” that sharks are likely to encounter and which “can also lead to abnormal pigmentation patterns”.
According to scientists, these disorders are linked to external factors such as temperature changes, exposure to pollutants or even genetic mutations. A consequence of geographical isolation which can favor the appearance of such anomalies.
The angular rough shark is “in danger”
The Adriatic, already worrying for marine fauna, could be the scene of genetic transformations linked to human activity, such as pollution or overfishing. Researchers therefore aim to better understand the mechanisms of these mutations and their impact on the survival of deep-sea species.
This closed sea with a Mediterranean climate is an ecosystem where several critically endangered marine species coexist, including the rough angular shark. The species is also classified “in danger” since 2020, on the red list of the International Union for Conservation of Nature (IUCN).
The appearance of this leucistic shark only accentuates the need to preserve these deep marine habitats, often ignored by conservation policies. This rare phenomenon could also be a signal of changes affecting deep marine ecosystems, reminding us of the urgency of developing appropriate protection measures.
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
