Sang-Man Cho

THE EFFECTS OF POLYCYCLIC AROMATIC HYDROCARBON EXPOSURE ON THE FERTILIZATION AND LARVAL DEVELOPMENT OF THE PACIFIC OYSTER, CRASSOSTREA GIGAS

Abstract To investigate the polycyclic aromatic hydrocarbon (PAH) effect on fertilization of the Pacific oyster, Crassostrea gigas, we exposed the adult brood stocks to PAHs (200 ppb) for 30 days as the treated (E group) with a nonexposed group as the control (C group). In addition, each subset of the gametes from both groups was further exposed to graded level of PAHs (0, 50, 100, and 200 ppb). Motile sperm and linearity were significantly affected by parental exposure, whereas straight line velocity (VSL) and curvilinear velocity (VCL) were affected by both of parental and larval exposure to PAHs. Fertilization and larval development were also affected by parental exposure. Our result suggests that fertilization capability and larval development are adversely affected by parental exposure whereas sperm movement was more vulnerable to larval exposure. In the brood stock contaminated by PAHs, larval development was also vulnerable to larval exposure to PAHs.

EFFECTS OF POLYNUCLEAR AROMATIC HYDROCARBONS ON HEMOCYTE CHARACTERISTICS OF THE PACIFIC OYSTER, CRASSOSTREA GIGAS

Abstract To investigate the effect of varying concentrations of PAHs and laboratory holding on hemocyte characteristics, Pacific oysters, Crassostrea gigas, were exposed to varying concentrations of polycyclic aromatic hydrocarbons for 40 days. The circulating hemocyte count (HC) was significantly decreased over the experimental day for all treatments including controls, by day 20; after 10 days, there were no differences among treatments. Similar pattern of decrease was observed over the experimental day in phagocytic index (PI) with relatively constant PI after 20 days. Statistical significance observed only at 10 days. Percent of mobile hemocyte (PMH) also exhibited significant decrease with an association of PAH concentrations without effect of laboratory holding. Lysosomal membrane destabilization (LD) increased continuously over the experimental day with exposed level-dependent differences. Our result indicate that PMH and LD are useful tools for biomarker with sensitivity to toxicant regardless of the effect of laboratory holding, however, HC and PI are significantly influenced by laboratory holding and exposure effect is negligible at the end of the experiment.

Effects of Water Temperature and Body Weight on the Filtration Rate of Sea Squirt Halocynthia roretzi

In order to understand the co-culture impact of the sea squirt Halocynthia roretzi on the Pacific oyster Crassostrea gigas, we examined the filtration rate of the sea squirt in relation of water temperature () and body weight. The filtration rate increased in relation to body weight and water temperature, indicating a clear positive correlation with the two variables. Due to the clear positive correlation between filtration rates at each temperature groups for acceptable collinearity, each constants at regression equation was further analyzed for a unified model of filtration rate. Therefore the filtration rate of H. roretzi was estimated as: Fr (L/h/animal)