Green sea urchin

Language English

Onglets

Description

Distinguishing features

Green sea urchins are round and covered with short spines less than 1 cm long. Between the spines are tube feet, for locomotion. The mouth, on the underside of the body, shows five fine white teeth. The animal is a greenish-brown colour.

Reproduction

Fertilization takes place externally. The larva, or echinopluteus, lives suspended in the seawater. Juveniles of more than 1 mm remain close to an adult, to be protected by its spines. Males and females are similar in appearance.

Diet

Sea urchins use their five small teeth to scrape fine algae off rocks, and also gnaw on large algae such as kelp. Although herbivorous, they sometimes feed on carrion as well. They can be found in lobster cages, where they eat the bait.

Predators

Green sea urchins are eaten by spiny starfish, Atlantic wolffish, cod, lobsters, seagulls, eider ducks and crabs, among others.

Habitat

They live in cold seawater, on rocky bottoms which they grip onto and move along with their long, fine tube feet. These sea urchins are typical of the tidal zone in the marine portion of the St. Lawrence. They can be found at depths of up to 800 m.

Ecology, behaviour

Green sea urchins are an edible species; people eat their sex glands, or gonads. There has been talk of marketing them. The animal feeds directly on shoreline algae and has a direct impact on their population (kelp in particular). Algae beds are an important habitat for many marine organisms and help to break the action of waves. A variation in the sea urchin population can affect the balance of the shoreline community.

French name

Oursin vert

Scientific name

Strongylocentrotus droebachiensis

Phylum

Echinodermata

Class

Echinoidea

Order

Echinoida

Family

Strongylocentrotidae

Size

Diameter: 7.5 cm

Status

Common species

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