Bryozoan fouling of the blue crab Callinectes sapidus at Beaufort, North Carolina

This study examines the prevalence, intensity, abundance, and spatial distr ibution of fouling bryozoans on 168 blue crabs, Callinectes sapidus, taken from an estuarine environment in the area of Beaufort, North Carolina. Thre e epizoic bryozoan species were found on the host crabs. These include Alcy onidium albescens Winston and Key, Membranipora arborescens (Canu and Bassl er), and Triticella elongata (Osburn). The proportion of blue crabs fouled was 16%. Results indicate female crabs were significantly more fouled than males. This suggests that the prevalence and intensity of bryozoans are dom inantly controlled by the migratory habits of the host, since female crabs spend more time in deeper waters of higher salinity where they are more lik ely to be fouled by bryozoan larvae. The ventral surface was significantly more fouled than the dorsal. The A. albescens colonies were significantly m ore abundant on the hosts' lateral spines, M. arborescens dominated the sub hepatic sector, and T. elongata was most common around the mouth. The costs and benefits of epibiosis are reviewed. The bryozoan/blue crab relationshi p described here appears to be phoretic. This means there is minimal negati ve impact on the crab, the relationship is more beneficial to the bryozoans , and there is no special symbiotic relationship between the crab and the b ryozoan.