National Geographic (Nat Geo) published on its social media the exact moment of the capture of the orange shark in Costa Rican Caribbean waters, which has amazed the world.
“A group of sport fishermen were casting their lines off the coast of Tortuguero National Park when one of their hooks caught a creature no one had ever seen before: a nearly two-meter nurse shark with white eyes and golden skin. “The astonished fishermen released the shark, but not before taking some photos to share with local scientists,” Nat Geo wrote in the post with the video.
And the caption adds: “At first, no one could believe it. “Many people said the photo must have been manipulated,” said Daniel Arauz Naranjo, Nat Geo explorer and executive director of the Costa Rican Center for the Rescue of Endangered Marine Species.
The post has more than 118,000 likes in a matter of 24 hours and more than 700 comments. The video was recorded in November 2024, but the images only recently emerged after being published in a scientific journal.
Why is the shark’s orange color?
Luis Hernández, a marine biologist at the National University and a fish specialist, explained to this media a few weeks ago that the nurse shark exhibits a condition called xanthism, which is rare in marine species.
It is also known as the nurse shark (Ginglymostoma cirratum) because it is characterized by having an elongated body and a rounded snout. “What happens is that it is normally a brownish-brown color. This is a species found in the Gulf of Nicoya and the Golfo Dulce, as well as in the Caribbean. These sharks feed on small crustaceans and some mollusks.
“In the shark found in the Caribbean, the pigmentation did not become carotenoid (a group of natural organic pigments found mainly in plants, algae, and some microorganisms), but rather orange. Very unusual,” he emphasized.
Hernández added that a possible explanation for this mutation in the shark’s color could be inbreeding. That is, this individual was the product of copulation or mating between two individuals who were related: mother with child or siblings.
Research Details
According to research by the Federal University of Rio Grande (Brazil), this shark had not previously been documented in cartilaginous fish (rays and manta rays) in the Caribbean.
However, this individual also has another condition: albinism, since its eyes are white. “The specimen was captured during a sport fishing excursion near Tortuguero National Park, at a depth of 37 meters and a water temperature of 31.2°C.
“The adult shark, approximately 20 centimeters in total length, had intense yellow-orange pigmentation and white eyes, indicating a condition known as albino-xanthochromism.
“This unique finding suggests that xanthism does not hinder the survival of this species. Compared to previous reports of abnormal pigmentation in G. cirratum, such as albinism, piebaldism, and hypomelanosis, this is the first scientifically documented case of total xanthism in the species and the first record in the Caribbean Sea.
“Further research is needed to explore possible genetic or environmental factors influencing this rare pigmentation abnormality in sharks,” reads part of the Brazilian research.
Piebaldism is the presence of depigmented areas on the skin, and hypomelanosis refers to the abnormal decrease or reduction of melanin in the skin or other pigmented structures, resulting in lighter coloration or partial depigmentation.”
