Molecular and morphological identification of Cardicola (Trematoda: Aporocotylidae) eggs in hatchery-reared and migratory Atlantic bluefin tuna (Thunnus thynnus L.)

0453655 - BC 2017 RIV NL eng J - Journal Article
Forte-Gil, D. - Holzer, Astrid S. - Pecková, Hana - Bartošová-Sojková, Pavla - Peñalver, J. - Dolores, E.M. - Muñoz, P.
Molecular and morphological identification of Cardicola (Trematoda: Aporocotylidae) eggs in hatchery-reared and migratory Atlantic bluefin tuna (Thunnus thynnus L.).
Aquaculture. Roč. 450, JAN 1 (2016), s. 58-66. ISSN 0044-8486. E-ISSN 1873-5622
R&D Projects: GA ČR GBP505/12/G112
Institutional support: RVO:60077344
Keywords : Aquaculture * Atlantic bluefin tuna * Blood fluke * Cardicola * Migration * Thunnus thynnus
Subject RIV: EG - Zoology
Impact factor: 2.570, year: 2016

A microscopic and a molecular approach was used to investigate blood fluke infection in the very first specimens of Atlantic bluefin tuna (Thunnus thynnus, Scombridae) that were born in captivity and that were never moved fromtheir specific cage culture sites in theMediterranean. Datawere compared with infection inwild, migratory bluefin tuna which were captured and fattened along the Spanish Mediterranean coast. Wild and cultured populations sampled in the present study harbored the same Cardicola spp. richness and showed statistically insignificant differences in overall parasite prevalence. Three morphotypes, crescent-shaped, fusiform and oval eggs, were observed in both non-migrant and migrant tuna. According to partial ITS2 and 28S rDNA sequences they belong to Cardicola opisthorchis, Cardicola forsteri, and to Cardicola sp., a recently described species, phylogenetically closely related to Cardicola orientalis. All three species were simultaneously present in some specimens. No significant difference in overall parasite prevalencewas observed, though the prevalence of eggs of individual species, i.e. C. opisthorchis and C. forsteri, was significantly higher in fattened bluefin tuna. Our results strongly support a Mediterranean origin of the three Cardicola species encountered in cultured specimens and suggest that the intermediate hosts of these Cardicola species occur along the Mediterranean coast. Thus, infection with these parasites is not exclusively a result of infections happening along the migratory routes of wild bluefin tuna, in the Atlantic Ocean, as previously suggested. Once transferred to the sea for fattening, Atlantic bluefin tuna are at risk of infection with up to three different species of the genus Cardicola in along theMediterranean coast in southeast Spain. On the contrary, C. orientalis infections might be associated to long-distance migration and an overlapping Thunnus maccoyii and Thunnus orientalis distribution.
Permanent Link: http://hdl.handle.net/11104/0254492