Mosaic Sea Star

Plectaster decanus

Plectaster decanus is a five-armed sea star known for its bright coloration. The upper surface is red with distinct raised yellow ridges, giving it a unique appearance that helps distinguish it from other sea stars. This species is soft to the touch and is one of the few poisonous sea stars, capable of causing numbness in humans if handled for extended periods. This sea star inhabits rocky reefs along the southern coast of Australia, typically found at depths ranging from 30 to 600 feet (10 to 180 meters). However, most recorded occurrences are shallower, with 90% found below approximately 20 meters. Its habitat preference for rocky environments makes it a common sight for divers exploring these regions. Feeding primarily on sponges, Plectaster decanus plays a role in the marine ecosystem as a predator of these organisms. Encounters with this species during dives can be intriguing due to its coloration and unique structure. Divers should exercise caution, given its venomous nature, and admire it from a safe distance. The conservation status of Plectaster decanus is not evaluated, indicating that there is no current information on its population trends.