Barnacles (Cirripedia, Thoracica) and associated epibionts from sea turtles in the central Mediterranean

Abstract

The association patterns and ecology of sea turtle epibionts, and especially obligate epibionts, are still poorly known. Epibiont communities were investigated in the central Mediterranean Sea in relation to the host habitat and seven species of barnacles, three amphipods, one crab, and one tanaid were found on 117 loggerhead sea turtles, Caretta caretta. Particular attention was given to barnacles, some of them being obligate turtle epibionts, with a total of 3330 individuals examined, among which high intraspecific aggregation was observed. Results indicate that (i) the species composition of barnacles varies among turtles frequenting not only different geographic areas but also different habitats in the same area, (ii) different species have marked preferences for hosts frequenting pelagic vs. benthic habitats, and also (iii) for body parts of the host representing microhabitats with different features and trophic opportunities, (iv) settlement is favoured by the presence of conspecific individuals and possibly also (v) by individuals of related species, notably Chelonibia testudinaria that may act as a pioneer species, and finally (vi) barnacles show rapid turnover on turtles, with relatively short lives, rapid growth, and high juvenile mortality.