First-ever 'golden nurse shark' found in Costa Rica’s Caribbean waters

Golden Nurse Shark Stuns Scientists in Costa Rica Waters (Image: Garvin Watson, shared by biologist shared by Marioxis Macías-Cuyare)

Divers off Costa Rica did not expect glittering gold. Rather than the typical grey or brown hues, they saw a nurse shark radiating with bright yellow-orange hues. The rare predator was discovered on a sport fishing expedition off Tortuguero National Park, 37 metres deep. Approximately two metres long, it represented an extraordinary first-time sighting of its type.

Rare Pigment Condition Explains Unusual Colour
Scientists confirmed the shark displayed a rare condition called xanthism. The disorder produces an excess of golden pigments in skin or scales. While xanthism has been recorded in some fish, it had never been confirmed in Caribbean sharks. This nurse shark is the first documented case worldwide. Its vivid colouring stands out sharply against seafloor environments where the species normally blends. Researchers suggest survival into adulthood is unusual for such a noticeable predator.

Albino-Xanthochromism Makes Shark Even Rarer
The shark’s white eyes hinted at another anomaly. Researchers say it also showed albino-xanthochromism, a rare combination of albinism and xanthism. The lack of melanin permitted the golden pigments to shine more intensely. This simultaneous condition makes the discovery all the more remarkable, as it necessitates two pigment pathways to be interrupted simultaneously.

Nurse sharks are still prevalent throughout the Caribbean but are under pressure from overfishing and habitat destruction. Researchers explain that unusual colour states emphasise genetic diversity among shark species. Conservation of their habitats ensures that even infrequent anomalies continue to live, providing new insights into marine evolution.

The study was published in the journal Marine Biodiversity.