1st Record: CA/Bodega Harbor (1974, Standing 1975, cited by Carlton 1979)

CA/Bodega Harbor (1974, Standing 1975, cited by Carlton 1979)

Level	Vector
Probable	Oyster Accidental

Ecological Impact		Competition
In Bodega Harbor, G. gemma was rare, until the arrival of the invasive Green Crab (Carcinus maenas), which preferred the larger Nutricola spp. In experiments, Gemma grew slowly in the presence of abundant Nutricola, but grew and reproduced much faster when Nutricola was rare (Grosholz 2005).

Species Regional Summary Gemma gemma _CDA_P112 (Bodega Bay) ( P112 )