Density, growth and reproduction of the sea urchin Anthocidaris crassispina (A. Agassiz) in two different adjacent habitats, the Sargassum area and Corallina area

Abstract

The sea urchin Anthocidaris crassispina (A. Agassiz) is a dominant herbivore on rocky shores in the warm temperate region of Japan. To clarify the relationship between macroalgal community and A. crassispina on rocky shores, A. crassispina collected in the Sargassum area and neighboring Corallina area were compared with respect to their density, growth and reproduction. Density of A. crassispina was higher in the Corallina area than in the Sargassum area. A. crassispina in the Sargassum area reached a larger size and had higher gonad indices than those in the Corallina area throughout the year. The annual reproductive cycles were almost the same in the two different habitats. These results indicate that Sargassum spp. support better growth and reproduction of A. crassispina.