Sea urchins
The pincushions of the reef — sea urchins graze on algae in rocky shallows and along walls. Long-spined species like Diadema can puncture wetsuits and booties, so watch your buoyancy near the bottom and never grab bare rock without looking.
Last updated April 2026
Sea urchin8 photos
A spiny, dome-shaped invertebrate — the common Mediterranean species is dark purple to black with long, sharp spines radiating in all directions.
Covers rocky surfaces in shallow water — watch your hands and knees near rocks. Spines are brittle and break off in skin, causing painful irritation.
© Jouni Kuisma
© Jouni Kuisma
© Jouni Kuisma
© Jouni Kuisma
© Jouni Kuisma
© Jouni Kuisma
© Jouni Kuisma
© Jouni Kuisma
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