Larval attachment and development of the monogenean Neoheterobothrium hirame under low water temperature

Abstract

Effects of low water temperature (below 10°C) on the oncomiracidial attachment and its subsequent development of Neoheterobothrium hirame were investigated. The cumulative attached larvae to the gill pieces from olive flounder Paralichthys olivaceus was reduced by 30% at 5°C when compared with 20°C. At 8°C the parasite development on flounder was significantly retarded compared at 20°C, and considerable number of worms disappeared from the host before reaching maturation. These results suggest low water temperature is a factor limiting the population growth of N. hirame in cold temperature regions. © 2005 The Japanese Society of Fish Pathology.