Morphological and Molecular Identification of Mullet Helminth Parasite Fauna from Ganzirri Lagoon (Sicily, Southern Italy)

SIMPLE SUMMARY: We investigated the role of mullet as a biological tag to evaluate environmental status, mainly in a specific and circumscribed area, between March and June 2021, by conducting a survey of 150 mullet caught from Ganzirri Lagoon (Messina, Sicily, Italy), in order to describe the helminth fauna. All retrieved parasite specimens were investigated by morphological and molecular analysis. Morphological evaluation allowed us to describe the Acanthocephalan Neoechinorhynchus agilis; however, identification of the digenean trematode Haploporus benedeni was only possible using molecular analysis. None of the parasite species isolated in the present study presents a risk to human health. ABSTRACT: Mullets (Osteichthyes: Mugilidae) are a euryhaline species widely distributed all over the world, thus representing an excellent study model for host–parasite interactions. From March to June 2022, 150 mullets, belonging to Chelon labrosus (n = 99), Chelon auratus (n = 37), and Oedalechilus labeo (n = 14) species, were caught to identify the helminth parasite fauna of the different mullet species present in the Ganzirri Lagoon (Messina, Sicily, Italy). A parasitological evaluation of the gastrointestinal tract (GIT) was carried out with a total worm count technique (TWC) to detect helminth presence. All collected parasites were stored in 70% ethanol until morphological evaluation, and frozen at −80 °C for subsequent molecular analysis, using 28S, ITS-2, 18S primers. The morphological evaluation allowed for the identification Acanthocephalan parasites (Neoechinorhynchus agilis) from two C. labrosus specimens. Sixty-six samples were positive for adult digenean trematodes (C. labrosus, 49.5 %; C. auratus, 27%, and O. labeo, 50%), molecularly identified as Haploporus benedeni. This study represents the first survey of helminthic parasite fauna of mullets from the south of Italy. The presence of Hydrobia sp. in the stomach contents of mullets allowed us to infer the H. benedeni life cycle in the Ganzirri lagoon.