Cannibalism among green sea urchins, Strongylocentrotus droebachiensis, in the laboratory and field
Cannibalism between size classes of the green sea urchin, Strongylocentrotus droebachiensis, occurs readily in the laboratory and the field. Adult and larger juvenile S. droebachiensis consumed 20 to 25% of small juvenile (3–6 mm) conspecifics over a 4 wk period in the laboratory. Gut content analyses of adults collected from the Gulf of the St. Lawrence indicated that cannibalism occurs frequently between size classes. Cannibalism rates were estimated to be between 0 and 68 urchins consumed m–2 wk–1, suggesting that cannibalism may be a major source of mortality for small juveniles in subtidal barren grounds.