Ecotype Variability of the Gastropod Ceratostoma burnetti from Pos'eta Bay (Sea of Japan)

This paper deals with the ecology, settlement, age structure, and shell variability of the gastropod Ceratostoma burnetti (Adams et Reeve) (Muricidae) from Pos'eta Bay (Sea of Japan). A change in the shell structure occurs between the open and inner bights of the bay: the shell sculpture smoothes, the ratio of body whorl diameter to height grows, the mass and degree of borer invasion of the shell increase, and, lastly, the relative mollusk size decreases. The given changes are hypothesized to result from borer influence as well as from differences in salinity and oxygen concentration in the studied regions.