Common Sea Urchin
Common sea urchins are found almost everywhere there is a rocky surface. Holding on with their tube feet, they use a set of jaws (5 teeth, of course!) to graze anything and everything off the rock. They are a bit like the marine equivalent of Harris sheep – they will eat everything in sight!
They will climb up kelp plants to chew away at the fronds, and devour sponges and weeds that encrust the rocks. Some areas are so heavily grazed that the only attached living thing left is the hard pink encrusting seaweed and cup corals, which are protected by their hard skeleton. In some places the urchins can’t hold on – vertical or overhanging rock faces, and places where the wave action is too strong – and like trees growing on a Harris cliff these places are covered with anemones, seasquirts and soft corals.
This urchin is sometimes known as the edible sea urchin – in the breeding season the normally empty shell fills with eggs, and these are considered a delicacy in some European countries.
Common Sea Urchin (Photo: Paul Tyler)
This urchin displays an impressive array of tube feet that it uses to hold on and move around. Urchins like this have grazed the rock clean of other plants and animals.
by Paul Tyler