In 2003, 13 isolates of iridovirus were obtained from cultured flounders Paralichthys olivaceus during epizootics in Korea. The full open reading frames (ORFs) encoding the major capsid protein (MCP) (1362 bp) from the 13 flounder iridoviruses (FLIVs) were sequenced and the deduced amino acid sequences were phylogenetically analyzed. Phylogenetic analysis of the MCP revealed that all 13 FLIVs were the same species as rock bream iridovirus (RBIV), red sea bream iridovirus (RSIV), and infectious spleen and kidney necrosis virus (ISKNV), and were grouped into an unknown genus which was different from the 2 genera known to infect fish, Ranavirus and Lymphocystivirus. This is the first report on the isolation and phylogenetic analysis of the iridovirus of unknown genus from flounders during epizootics.

The development of swift's scallop Chlamys swiftii, reared in the laboratory, has been examined through the investigation of morphological characteristics in fertilized egg, larvae and juvenile. Eggs were fertilized with a dilute sperm solution to improve the survival of fertilized eggs. Developing larvae were maintained at a temperature of 16 ± 0.5℃ and salinity concentration of 33 ppt. We have investigated the fertilization rates and egg number spawned at several stimulating conditions such as sunlight exposure, air dry, seawater temperature rise (5℃) and seawater temperature rise (5℃) after exposure of air dry for spawning induction of swift's scallop Chamys swiftii. Stimulation treated with sunlight exposure and seawater temperature rise (5℃) have shown the spawning number of 700,000-900,000 and 700,000-800,000 per individual, respectively while stimulation treated with seawater temperature rise (5℃) after exposure of air dry have shown the high spawning number of 1,000,000-1,500,000 per individual. Survival rate of D-shaped larvae of swift's scallop put into the different seawater temperatures of 8℃, 1 2℃, 16℃, 20℃ and 24℃ has been 4.1%, 11.6%, 32.7%, 18.6% and 3.2%, respectively. Fertilized eggs with the diameter of 72 μm developed into trochophore larvae of 103 ± 3.8 μm shortly after 35 hours and to D larvae of 129 ± 10.4 μm shell length within 72 hours. It took 336 hours to become initial Umbo-stage larva of 145 ± 16.8 μm shell length. Post larvae, which have been 197 ± 13.6 μm shell length, spontaneously have settled in the attachment substances. It have required 528 hours from fertilized eggs to early attached juvenile to become initial juvenile size of 245 ± 15.8 μm shell length.