FEEDING-CURRENT INTERACTIONS AND COMPETITION FOR FOOD AMONG THE BRYOZOAN EPIPHYTES OF FUCUS-SERRATUS

Flustrellidra hispida (Fabricius), Alcyonidium hirsutum Fleming and Electra pilosa (L.), generally the three most abundant bryozoan epiphytes of the intertidal brown alga Fucus serratus L, were collected around low-tide mark at Port St. Mary, Isle of Man (UK), during 1983 and early 1984. Flustrellidra hispida is far larger than the other two species. Direct measurements of feeding-current velocities within the lophophores of competing colonies indicate that F. hispida is able to adversely affect the feeding of adjacent colonies of competing bryozoan species. Results suggest that among the bryozoan community of Fucus serratus, competition for food and for space are closely linked and that both are significant components of interspecific competition.