Species and Habitat Outlines

Red Sea Urchin

Phylum: Echinodermata
Class: Echinoidea
Order: Echinoida
Family: Strongylocentrotidae



Distribution: rocky areas throughout exposed and protected coastal waters.

Habitat: rocky substrates, especially ledges and crevices; locate near or in giant or bull kelp beds and other brown algae in areas of moderate to swift currents; larvae drift and feed in plankton; juveniles settle near kelp beds, often associate with aggregations of adults, remain under adult spines until they reach 40 mm.

Tidal elevation: extreme low tide to 100 m subtidal depth; most concentrated abundance just below the upper limit of range, usually 5-10 m subtidal.

Food: herbivore; grazes on attached marine plants and drifting kelp fragments; primary food is kelp and may limit kelp distribution.

Predators: sea stars, sea otter, octopus, crabs, wolf eels; numerous predators on larvae.


Slow, very dependent on food (i.e. kelp) supply; sexually mature at 50 mm test diameter reached at 2 yr; reaches commercial size, 100 mm at 4-5 yr; may reach 190-200 mm test diameter.


Small commercial diving fishery; minimum size limit 100 mm; 1986 commercial catch was 2,067 t valued at $1 million.


Bernard, F.R. 1977. Fishery and reproductive cycle of the red sea urchin, Strongylocentrotus franciscanus, in British Columbia. J. Fish. Res. Board Can. 34: 604-610.

Breen, P.A. 1984. Sea urchins: suitability of the present minimum size limit, p. 25-51. In G.S. Jamieson [ed.] 1982 shellfish management advice, Pacific Region. Can. MS Rep. Fish. Aquat. Sci. 1774.

Jamieson, G.S., and K. Francis. 1986. Sea urchins, p. 8-12. In G.S. Jamieson and K. Francis [ed.] Invertebrate and marine plant fishery resources of British Columbia. Can. Spec. Publ. Fish. Aquat. Sci. 91. Kato, S., and S.C. Schroeter. 1985. Biology of the red sea urchin, Strongylocentrotus franciscanus, and its fishery in California. Mar. Fish. Rev. 47: 1-20.

Mottet, M.G. 1976. The fishery biology of sea urchins in the Family Strongylocentrotidae. Wash. Dep. Fish. Tech. Rep. 20: 66 p.

Sloan, N.A. 1986. World jellyfish and tunicate fisheries, and the Northeast Pacific echinoderm fishery, p. 23-33. In G.S. Jamieson and N. Bourne [ed.] North Pacific workshop on stock assessment and management of invertebrates. Can. Spec. Publ. Fish. Aquat. Sci. 92.

Sloan, N.A. 1986. Red sea urchin. Underwater World, Fish. Oceans Can., Ottawa: 4 p.


For more information on red sea urchin habitat utilization and life cycles - click here

Return to Species Index