Urchin removals were conducted to improve local fishing grounds, and to test the effect of urchin removals on restoration of seaweed beds.
Site Selection Criteria:
Three 50m × 50m square blocks were established on urchin barren boulder beds at depths between 4 and 8m, where kelp was not present.
Cause Of Decline:
Along the southwestern coast of Hokkaido, low-productivity urchin barrens caused by the sea urchin Strongylocentrotus nudus have persisted for ~80 years, restricting kelp beds comprised of Saccharina japonica var. religiosa and Undaria pinnatifida to shallow waters largely less than 2m in depth as a grazing refuge.
Restoration of kelp beds on an urchin barren: removal of sea urchins by citizen divers in southwestern Hokkaido
Bull. Fish. Res. Agen, Vol. 32.https://www.researchgate.net/...ers_in_southwestern_Hokkaido