Biotic action in fouling communities on edible shellfish – oysters (Ostrea edulis LINNAEUS) and mussels (Mytilus galloprovincialis LAMARCK) in the northern Adriatic

Abstract

      On marked oysters and mussels during 2 and 3 years were observed "in situ" characteristics and changes of epi­bionts from their occurrence until their death. On the basis of these characteristics (occurrence, habit, manner and rate of growth, vitality, relation to substratum and season, affinity of individuals of the same species, relation imigration-emigration, and particularly the process of direct and indirect biological exclusion) all organisms were classified into 5 different types (from superior to subordinate epibionts). The same epibionts were further on divided into active, inactive and subordinate organisms according to their biological acti­vity (participation in the process of biological exclusion).

      Besides the division of epibionts, some other analytical marks were elaborated for the same organisms: frequency, abudance and covering rate.