Nippon Suisan Gakkaishi 71 (5), 762-767 (2005)

Seasonal changes in oxygen consumption rates and filtration rates of the cultured Pacific oyster Crasssotrea gigas

SATORU AKASHIGE,* YASUSHI HIRATA, KEISUKE TAKAYAMA AND KIRIE SORAMOTO

Hiroshima Fisheries Experimental Station, Hiroshima 737-1207, Japan

The oxygen consumption rates (OCR: mgO2/h/ind.) and filtration rates (FR: L/h/ind.) of the cultured Pacific oyster Crassostrea gigas in different sizes were measured in a still water system at different seawater temperature in various seasons. OCR of each oyster were measured for three to four hours in a closed chamber of 1 or 5 litters, according to the size of each animal. FR of each oyster were measured by determining the removal rates of particles of cultured diatom Chaetoceros calcitrans, which were suspended initially in filtered seawater of 30 litters at concentrations of 5-6×104 cells l-1.

For each temperature allometric relationships (OCR or FR=aWbd) between these rates and dry-flesh weight (Wd, g) of the oyster were estimated. In case of OCR parameter b was 0.75±0.10 (mean±standard deviation), showing no relationships with seawater temperature. The value of parameter a varied according to seawater temperature(t) over the range (11.6-26.5°C), and OCR were expressed by the formula: OCR=(0.072t-0.64)Wd0.75.

In case of FR the value of parameter b was 0.96±0.24, showing no relationship to seawater temperature. The value of parameter a varied according to seawater temperature over the range (9.7-25.7°C), and FR were expressed by the formula: FR=(0.70t-6.6)dW in non-spawning season. In spawning season, when the value of a were constant around 4.9, which was lower value than that expected by the formula applied in non-spawning season, FR were expressed by the formula: FR=4.9dW.


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