Sea Urchin

Black Sea Urchin (Arbacia lixula)

• Size: Up to 5 cm in diameter

• Appearance: Round, dark purple to black shell covered in sharp spines

• Habitat: Rocky seabeds, crevices, and seagrass areas

• Behavior: Slow-moving grazers that feed on algae, playing an important role in maintaining healthy reef ecosystems

• Notes: Their sharp spines can cause painful wounds, so avoid stepping on or touching them while diving or snorkeling.

Sea urchins are a familiar and important part of Crete’s marine landscape, commonly found clinging to the rocky shores and seabeds, especially in clear, shallow waters where sunlight nourishes the surrounding algae. The most frequently encountered species include the black sea urchin (Arbacia lixula), recognizable by its dark spiny shell, and the edible purple sea urchin (Paracentrotus lividus), prized not only for its striking appearance but also as a sought-after delicacy in Mediterranean cuisine. Although their sharp spines can cause painful stings if accidentally stepped on, these spines are not venomous. Sea urchins play a crucial role in the ecosystem by grazing on algae, which helps prevent overgrowth that can smother coral and other marine life, thus maintaining a balanced underwater environment. Their presence indicates a healthy reef system, but harvesting of some species is strictly regulated to ensure the sustainability of local populations and protect the delicate marine habitats. For snorkelers and divers exploring Crete’s coastal waters, spotting sea urchins nestled among the rocks is both common and a reminder of the intricate web of life beneath the surface.