Long-term Dynamics of Infection of Fish Eggs and Larvae with the Endoparasite Ichthyodinium sp. (Dinoflagellata) in Nha Trang Bay, Vietnam

Results of long-term investigation of infection prevalence of fish eggs and larvae with the endoparasite Ichthyodinium sp. (Dinoflagellata) in Nha Trang Bay (South China Sea, Vietnam) are presented. The parasite was identified on the base of morphological characteristics and phylogenetic analysis with 18S rRNA sequences. After the first record in 1993 the infection rate steadily increased till 2004, remainded high in 2004-2007, decreased in 2008-2009 and again boosted in 2010. Seasonal and annual dynamics of the infection rate was described. The parasite showed different degrees of prevalence in different taxonomic groups of fishes. The infection rates were different among closely related species. This is the first report on long-term dynamics of Ichthyodinium infection in Southeast Asia.