Biological Diversity and Parasitological Peculiarities of Myxosporea (Cnidaria, Myxozoa) Infecting Merluccius Merluccius (Linnaeus, 1758) in the Sea of Marmara.

Abstract

PURPOSE: This study aimed to investigate the biodiversity and parasitological peculiarities of myxozoan parasites infecting European hake, Merluccius merluccius, one of the most commercially important demersal fish species, in the Sea of Marmara, Türkiye. METHODS: A total of 47 M. merluccius specimens were collected from the eastern coasts of the Sea of Marmara and examined for myxozoan infections. Morphological observations, morphometric measurements, and phylogenetic analyses based on 18 S rDNA sequences were conducted to identify the parasites. RESULTS: Of the 47 fish specimens examined, 12 were infected by two distinct myxozoan species. One was identified as Pseudalataspora vanderlingeni based on morphology, morphometry, and molecular data. The second species, Ceratomyxa sp., which could be identified to the genus level based solely on spore morphology, was consistently found co-infecting fish hosts of the previously identified parasite species. Notably, its spore morphology differed from that of the six Ceratomyxa species previously recorded in Turkish marine waters. CONCLUSION: This study presents the second global record of Pseudalataspora vanderlingeni since its original description, representing the first report of both the species and the genus Pseudalataspora in Turkish waters. Additionally, a new Ceratomyxa taxon from the same region in Turkish waters was also documented. Together with the previous reports, the results in this study suggest that P. vanderlingeni is a common myxozoan parasite of Merluccius species along the southern Atlantic coasts of Africa, with its range extending into the Mediterranean Sea and surrounding waters. Additionally, this study also presents Ceratomyxa as one of the possible common myxozoan parasites of Merluccius species in the Mediterranean and adjacent seas.