2008 Volume 1 Issue 2 Pages 45-60
Algal succession after removal of Strongylocentrotus nudus population from the sea urchin-dominated barren ground (ISOYAKE) was observed on the coasts of Sai, Shimokita Peninsula, Japan, in order to clarify the procedures for the restoration of edible seaweed communities of Saccharina japonica. Strongylocentrotus nudus population (c.a. 44k-194k) was removed from the eight areas (1.2-4.15 ha) of the depth of 4-13 m in each year of 1994 to 2001. Standing crops and covered ranges of seaweed were measured from February 1995 to June 2002 in the S. nudus removal and non-removal area, respectively. Young sporophytes of S. japonica occurred on February 1995 in the removal area of S. nudus population that was removed on September 1994. After that, S. japonica dominated the standing crops of seaweeds and the maximum standing crop of 10.1kg/m2 was recognized on June 1996. Dominant communities of S. japonica occurred also in other seven removal areas within a year from the removal of S. nudus population. And the S. japonica communities were observed successively for a maximum of eight years, though S. nudus swarmed to graze on them. On the other hand, ISOYAKE had continued in the non-removal area. From these results, the S. japonica communities were considered to be restored by the removal of S. nudus population from ISOYAKE on this investigation coast.
