EFFECTS OF DIET ON LIFE-HISTORY PARAMETERS OF THE MARINE BRYOZOAN, CELLEPORELLA-HYALINA (L)

In order to maintain constant environmental conditions during experimental work on the marine bryozoan Celleporella hyalina (L.), it was necessary to develop a simple and inexpensive culture method. C. hyalina survived and grew on a range of algal diets. Amongst these, chlorophyte algae proved least suitable, but the cryptophyte Rhodomonas baltica was found to be outstanding as a foodstuff. Astogeny of Rhodomonas-fed colonies was similar to that reported for naturally occurring colonies, and resulted in the production of viable larvae. Female zooids were occasionally produced in the basal layer. Using R. baltica as food, C. hyalina can be maintained under controlled environmental conditions indefinitely. This, together with the possibility of propagating clonal replicates of colonies, facilitates the experimental investigation of life-history variation in C. hyalina.