Blood fluke diseases in Pagellus spp. (Sparidae): Pathology and description of a new species of Skoulekia in the blackspot seabream P. bogaraveo (Brünnich)

Pagellus bogaraveo (Brünnich) and P. erythrinus (L.) (Perciformes, Sparidae) are highly appreciated by Mediterranean consumers and good candidates for the Mediterranean aquaculture diversification. Parasitological and histological analyses of both sparid species, collected off Santa Pola (Spanish Mediterranean), have been performed in order to detect blood flukes (Trematoda, Aporocotylidae) and the pathologies related to their presence in these valuable hosts. Eggs of two different species of Skoulekia Alama-Bermejo, Montero, Raga and Holzer, 2011 have been found in both fishes: S. erythrini Palacios-Abella, Georgieva, Mele, Raga, Isbert, Kostadinova and Montero, 2017 in P. erythrinus and S. bogaraveo n. sp. in P. bogaraveo. Both parasite species showed differences in egg distribution inside the host gill vessels apparently related to their different sizes. The adult blood flukes were also located in specific microhabitats in the host such as the kidney, heart, gills, in the case of S. erythrini, and the brain in the case of S. bogaraveo n. sp. The distribution of each species implies alterations at different host areas, probably leading to different pathologies. Morphological and molecular studies support the specific identity of S. bogaraveo n. sp. The new species differs in its slender body, more conspicuous and lobed testis and the shorter and less numerous tegumental spines. Highly transmission rates and pathogenic potential of this species suggest considering aporocotylidoses as possible emerging diseases for the culture of these sparid species.