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Green Sea Urchin, Northern Sea Urchin

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Echinoderm

Green Sea Urchin, Northern Sea Urchin

Strongylocentrotus droebachiensis (O.F. Müller, 1776)

WoRMS AphialID

124321

Sample IDs

Collected

Eastern Shore NS, SCUBA hand collection on large boulders with kelp, 19 m depth.

Distinguishing Features

• Test: globular and radially symmetric in shape with the mouth in the centre on the oral surface and the anus in the centre of the aboral surface. Dark green in colour and may be tinged with purple or red.
• Spines: prominent short green-brown spines with largest spines in distinct vertical rows.
• Size: to 100 mm in diameter and to 45 mm in height.

Habitat

Primarily found on hard substrates such as cobble, boulders and gravel, and occasional sandy areas, shallow subtidal to 1200 m depth.

Geographic Range

Circumpolar distribution of the Northern Hemisphere ranging from the Arctic to Washington in the Pacific Ocean and to New Jersey in the Atlantic Ocean.

Fun Fact

If sea urchins become too abundant, they can create areas with no kelp. These are known as urchin barrens. But if there aren’t enough urchins, kelp may become over-abundant. It is important to manage outside pressures as far as possible to keep the ecosystem balanced. Infection by the amoeba Paramoeba invadens sometimes causes mass mortality of sea urchins. Green sea urchins are also fished commercially in the Bay of Fundy – their gonads are edible and regarded as a delicacy by some people.

Barcode Distribution

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