Philometroides seriolae Recovered from the Swimbladder of Japanese Amberjack Seriola quinqueradiata

Abstract

A dead nematode was recovered from the swimbladder of a one-year old cultured Japanese amberjack Seriola quinqueradiata. ​Microscopically, the nematode had many bosses on the body surface and contained mass of larval nematodes inside the body, suggesting the parasite was a mature Philometroides seriolae. ​Molecular analysis of its body part confirmed the identity of the parasite. ​This is the first record of infection site of this nematode beside the skeletal muscle from the fish host. ​The amberjack had most likely been infected with the nematode before introduced to the farm. ​The possibility of errant parasitism in this case is discussed.