Molecular genetic identity of species found in loggerhead sea turtles in Maltese waters

Abstract

Loggerhead Sea turtles are migratory animals that travel the warm oceans of the world for food, mating, and nesting. They are enlisted as globally Vulnerable under the IUCN Red List. The threats sea turtles face include loss of nesting sites, pollution, and fishing activities. They have a brown carapace with hexagonal patterns which may have several species growing on it. These associated species may include filter feeders such as several species of barnacles, but also other species such as crabs, amphipods, isopods, and algae. Genetic confirmation of the associates’ identities, accompanied by research, may provide information on the biodiversity associated with sea turtles, their health and behaviour. The purpose of this study served to add more genetic data to understand sea turtles in the Maltese waters. An ERA permit was issued to Professor Adriana Vella, to handle wild sea turtles and their epibionts. Tissue sampling prepared the epibiont samples for DNA extraction by Proteinase K and for amplification by PCR. The barcoding marker used is COI since it has a relatively slow mutation rate and lacks recombination. DNA barcoding offers precise species identification allowing accurate research to be conducted. The amplicons, confirmed by gel electrophoresis were purified and analysed through Sanger sequencing. The sequences were trimmed and checked for inconsistencies. The results were compared to sequences in BOLD and GenBank. A total of 99 specimens were analysed, which led to the identification of nine species of epibionts. From the analysed specimens there was a total of 34 different haplotypes of which 26 were new to both BOLD and GenBank. Two species of Planes crabs were found (Planes minutus and Planes marinus) and a total of seven new haplotypes unknown to BOLD and GenBank were identified. Additionally, three species of barnacles were collected (Platylepas coriacea, Conchoderma virgatum and Chelonibia testudinaria). From these, seventeen new haplotypes were discovered. One new haplotype was found from the amphipod species (Podocerus cf. pyurae and Caprella andreae). No new haplotypes were found for the isopod (Idotea metallica) and one was found from Melanothamnus sp.