Fishers discover first-of-its-kind bright orange shark with two rare conditions in Caribbean
A first bright orange shark with white eyes was captured and released in the Caribbean, reveals a new study.
The nurse shark (Gantmostoma Cirratum) had a mysterious condition called Xanthism, or Xanthrochroism, which increases yellow pigmentation in the skin. The researchers recorded Xanthism in several animals, but it is the first final case of a nurse shark with the line. The shark also seems to have albinism, making it even more unusual.
The sports fishermen discovered the shark by chance off the east coast of Costa Rica in 2024. Garvin Watson, owner of the Parismina Domus Dei hotel in the village of Parismina, wrapped in the shark, which was about 6.6 feet (2 meters) long and swimming 120 feet (37 m) below the surface.
“We couldn’t believe what we had before our eyes,” Watson told Live Science in an email.
“This brilliant orange shark with sunlight was something out of the ordinary,” he said. “We did not know that it would be a discovery worldwide, recognized by all biologists in the world.”
The fishermen photographed the shark, then removed the hook from his mouth and released him in the Caribbean Sea. The researchers described the event and its meaning in a new study published on August 1 in the journal Marine biodiversity.
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Scientists have documented xanthism in a variety of species, including frogs, birds and fish. While some animals are normally yellow and orange, these colors are more important in xanthic individuals of these species.
The nursing sharks are generally yellow to gray brown. There have been occasional relationships of unusual coloring in this species, in particular albinism – Characterized by a complete lack of melanin pigmentation in the skin and iris – and potential xanthism, but a Xanthic nurse shark had never been scientifically documented before, according to the study.
“We were very surprised and excited when we saw the [xanthism] In the photos, “principal author of the study Marioxis Macías-CuyareA doctoral student in biological oceanography at the Federal University of Rio Grande in Brazil, told Live Science in an email.
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The researchers spoke with Watson and studied the photos of the shark. They noted that the shark did not have the black iris generally seen in the shark eyes and concluded that it was probably albinos and xanthic. A 2018 study documented this combined condition, known as xanthochromism albinos, in a species of radius (Raja Montagui) found in the Irish Sea.
Researchers still study the causes of abnormal pigmentation in sharks. Such conditions are generally associated with genetics, but factors such as environmental stress, high temperatures and hormonal imbalances can also contribute to different colors, depending on the study.
Macías-Cuyare said xanthism is generally genetic, but no more research was necessary to understand the conditions influencing the abnormal pigmentation of the shark.
The Shark survival is also curious. The animals evolve to be specific colors to better survive in their environment, so being bright orange when the species is not supposed to be normally an obstacle. In this case, the shark reached adulthood and does not seem to have been retained by its unusual color.
“Many factors influence this, such as the environment, but everything remains speculative until the variables that could influence this genetic condition are tested,” said Macías-Cuyare.
