Infestation of Lernaeenicus seeri (Copepoda: Pennellidae) and Hirudinella ventricosa (Digenea: Hirudinellidae) on wahoo Acanthocybium solandri collected from Parangipettai, southeast coast of India.

A commercially important fish, wahoo Acanthocybium solandri (Cuvier, 1832) (Scombridae), was collected to study the infestation of parasites from Parangipettai landing center, Tamil Nadu, southeast coast of India for a period of one year from January to December 2011. A total of 644 fish were captured and screened for parasites. Off 644 fish, 270 were infested by a parasitic copepod Lernaeenicus seeri Kirtisinghe, 1934 (Siphonostomatoida: Pennellidae) on the body surface. It is a mesoparasite, since the head and neck are inserted and attached to the muscle by making a wound/hole on the body and the rest of the parasite body with the egg sacs hanging outside. Prevalence was recorded as 42.29% with mean and maximum intensity at 3.22 and 33, respectively. Seasonal study showed that the prevalence was highest (62.82 %) during postmonsoon. Simultaneously, some of the fish (n = 144) were internally observed for the presence of parasites and we found that 101 fish were infested with an endoparasite digenean Hirudinella ventricosa (Pallas, 1774) (Hirudinellidae) in the stomach. Prevalence was recorded as 70.9%, and mean intensity of 1.62 and maximum intensity of 3 were also noted. The overall percentage of both copepod and digenean infestation were recorded as 60.42%. The infestation was high in postmonsoon season for both parasites. This is the first record of L. seeri from Indian waters and the second record of occurrence worldwide. Significant interactions were observed between season and infestation of both parasites (P<0.05).