Recent Developments in the Japanese Oyster Culture Industry

Heat shock protein (hsp70) expression and thermal tolerance in sublethally heat-shocked eastern oysters Crassostrea virginica infected with the parasite Perkinsus marinus

“…This is important as heat shock could be utilized as a way to improve survival in diseased oysters. Techniques to harden animals, such as intertidal culture, are often employed to improve survival of oysters and reduce fouling (Ventilla 1984, Handley & Bergquist 1997). An understanding of the heat shock response and its role in thermal and pathogenic stress is important to improve survival in cultured bivalves.…”

Growth and reproduction of early grow-out hardened juvenile Pacific oysters, Crassostrea gigas in Gamakman Bay, off the south coast of Korea

“…This process is called "hardening" and it has been practiced commonly in Korea and Japan oyster aquaculture for the past decades. During hardening, growth and reproduction of the spats are suppressed due to periodic exposure to atmosphere and subsequent reduced feeding time (Fujiya, 1970;Ventilla, 1984;Arakawa, 1990;Choi, 2008). Eight to 10 months after hardening, the stunted oyster spats are transplanted to the long-line hanging culture facility in May and harvested in November.…”

“…Eight to 10 months after hardening, the stunted oyster spats are transplanted to the long-line hanging culture facility in May and harvested in November. According to Fujiya (1970) and Ventilla (1984), the survival rate of the hardened oysters in Hiroshima waters was 70-90%, while the rate was only 20% with no hardening. After 6-8 months of grow-out, the hardened oysters reach over 80 mm in shell length and 5-6 g in tissue wet weight (Kang et al, 2000(Kang et al, , 2010Hyun et al, 2001).…”

Prevalence and infection intensity of the ovarian parasite Marteilioides chungmuensis during an annual reproductive cycle of the oyster Crassostrea gigas

“…For successful seed production and ultimately oyster production, studies on seasonal changes in gonadal maturation and impacts of environmental parameters on reproduction are essential for the Korean oyster industry. Over 170 000 metric tonnes of oysters were produced in Korea in the year 2000 from the intensive suspended longline culture system, making Korea one of the world's largest oyster exporters (Ventilla 1984, FAO 1999.…”