COMMUNITIES OF EPIBIOTA ON 2 ERECT SPECIES OF ANTARCTIC BRYOZOA

Two erect species of bryozoans, Alloeflustra tenuis (Kluge) and Nemato flustra flagellata (Waters), occur abundantly in similar localities at Signy Island, Antarctica. Both species are unilaminar and are coloniz ed by a range of epibiotic taxa, principally other cheilostome bryozoa ns. A detailed study was undertaken of the bryozoan epibiota of these two species, collected by SCUBA over the depth range 36 to 40 m. The d egree of colonization varied with host size and differed between the f ront and rear surfaces of each host species, and between host species. The species composition of the epibiota was also different between sp ecies and between surfaces within species. These variations are possib ly related to differences between the host species in the abundance, s tructure and function of avicularia (putative protective structures). Specimens from deeper water (150 m) showed significantly reduced colon ization by epibiota, but the same overall patterns of colonization bet ween the two species and surfaces were still observed.