Ectoparasite fauna of the lebranche mullet, Mugil liza, from a coastal lagoon in the Southwestern Atlantic.

Coastal lagoons are among the most productive aquatic ecosystems worldwide and are widely used by mugilid fishes. Mugil liza stands out as one of the main resources of lagoon fisheries in southern and southeastern Brazil. This study aimed to identify the species composing the ectoparasite fauna of M. liza from the Maricá Lagoon, Rio de Janeiro State, Brazil. A total of 44 specimens of M. liza were examined, of which 95.4% were parasitized by at least one ectoparasite species. Six ectoparasite species were recorded. The copepod Ergasilus caraguatatubensis was the most representative species, with prevalence (P) of 86.4%, followed by the copepods Bomolochus nitidus (P = 43.2%), Caligus sp. (P = 2.3%) and Naobranchia lizae (P = 2.3%). The polyopisthocotylan Metamicrocotyla macracantha showed prevalence of 18.2% and the myxozoan Myxobolus episquamalis presented a low prevalence (P = 2.3%). The ectoparasite fauna of M. liza exhibited diversity, comprising six distinct families, highlighting the host's gills as an important site for parasite diversity. The results expand the environmental distribution of E. caraguatatubensis, B. nitidus, Caligus sp., N. lizae and M. macracantha within Rio de Janeiro State, increasing the known occurrence sites of these parasites, including lagoon.