Epibiontic associations between apostomid ciliates Conidophrys spp. and amphipods associated with fish farms fouling in the western Mediterranean Sea

Fish farms commonly support high abundances of invertebrates, especially amphipods, associated with fouling communities developed over nets, ropes and buoys. Protozoan epibiont ciliates of the genus Conidophrys were observed on three of the most abundant amphipod species collected from ropes of a fish farm in the western Mediterranean Sea. The amphipod species were Ericthonius punctatus that presented the epibiont Conidophrys pitelkae, and Jassa marmorata and Jassa slatteryi with the epibiont C. pilisuctor. The epibionts were found in numbers fluctuating between 1 and 119 individuals in Jassa spp. (median value = 8), higher than the number of epibionts found on E. punctatus that varied between 1 and 39 individuals (median value = 3). The epibiosis on Jassa spp. also showed prevalence values (34.33 %) superior to those of E. punctatus (24 %). Differential distribution of the epibiont species on the surface of basibionts was detected: Conidophrys pilisuctor were more frequently found on the head and gnathopods of Jassa spp., while C. pitelkae were mainly counted on the head of E. punctatus. This is the first time that Conidoprhys were found on these amphipod species