A rare golden shark has been seen for the first time in the world. Local sport fishers recently spotted it off the coast of Costa Rica. Last summer, fishing near Tortuguero National Park, they caught a six-foot nurse shark with white eyes and a golden body. No one had ever seen a shark of such an unusual colour before.

The shark was released at once, but the fishers took photographs and sent them to local researchers. At first many suspected the pictures were fake, but experts later confirmed they were real. They said the shark's unusual colour came from a rare skin condition called albino-xanthochromism.

Albino-xanthochromism is essentially a combination of two genetic conditions. In albinism, a lack of melanin makes the skin, hair and eyes pale. Xanthism, on the other hand, gives an animal an abnormal yellow or orange colour.

Researchers say the two are usually seen separately, but this is the first case of both traits appearing together.

Nurse sharks are normally brown, so that they blend in with the sand on the sea floor. This camouflage helps them catch prey and escape predators. But this golden shark clearly stands out.

Yet, surprisingly, the shark was fully grown and healthy. Experts believe it was able to survive because it lived in the murky water of a river mouth.

Shark researcher Melissa Cristina Márquez called the discovery "fascinating", saying it is proof that there can be so much variety even within species we think we know well.

Researcher Daniel Naranjo says the shark's presence matters not only for science but also for Costa Rica. In future, tourists may head out to sea hoping to see it up close.

The report cites National Geographic.

Source: Jagonews24. First published in Bengali on The Agro News.