2003 Volume 58 Issue 1 Pages 1-6
Abstract: The occurrence of the green alga Cladophora conchopheria on shells of the intertidal gastropod Turbo coronatus coreensis was examined at a bay in central Japan. The shells were consistently fouled predominantly by C. conchopheria. Observation of cross-sections of the shells by SEM revealed that false roots of C. conchopheria penetrated through the periostracum and into the outer ostracum of the shells. Field observations showed that C. conchopheria was uncommon or absent in the innermost parts of the bay, where the substrata were composed partially of mud and T. coronatus coreensis was common. A transplant experiment revealed that the alga could not newly colonize shells or maintain their colonization at one of the innermost stations. After the death of the snails, the abundance of C. conchopheria on shells did not change for3months and then decreased gradually, probably as a result of tearing of the periostracum layer. We saw no new algal colonization on dead snail shells even after8months. Most colonization of living snails occurred on the shell part nearest to the aperture, indicating that algal colonization occurred primarily in the area of the new shell growth.
