Treatment of Microcotyle sebastis (Monogenea: Polyopisthocotylea) infestation with praziquantel in an experimental cage simulating commercial rockfish Sebastes schlegeli culture conditions.

The antiparasitic efficacy of praziquantel against the blood-sucking polyopisthocotylean Microcotyle sebastis was tested in an experimental cage simulating commercial rockfish-culture conditions. Juvenile rockfish Sebastes schlegeli were separated into 4 pilot net-pens, and the fish in the groups were either fed a control diet (Group C), fed a praziquantel-adsorbed diet (Group F), bathed in 100 ppm praziquantel for 4 min (Group B), or bathed in 100 ppm praziquantel for 4 min and then fed a praziquantel-adsorbed diet (Group BF). The results of the present study indicate that feeding a praziquantel-adsorbed diet significantly reduces the abundance of M. sebastis infestation, and bathing in 100 ppm praziquantel for 4 min is effective for controlling M. sebastis infestation in practical rockfish culture systems.