Growth Model of Oyster in Oginohama Bay near Miyagi Prefecture, Eastern Japan

Abstract

As the fi rst step in the calculation of an appropriate quantity of oyster, we conducted growth tests of oyster and environmental observations in Oginohama Bay, and formulated a growth model of oyster by improving parts of a model for Hiroshima prefecture, western Japan. For the main improvements, we devised a calculation formula of the oxygen consumption rate OCR = 0.0012×t2.16×Wd 0.75（t; temperature, Wd; dry weight）, and fi ltration rate, FR = 0.26e（0.1584×t）×Wd in low temperature. Although other set conditions were basically the same as those used in the Hiroshima model, this modifi ed growth model of oyster is applicable for the Tohoku area where the water temperature from winter to spring is below 10 degrees. Although the oyster grows rapidly from early summer in the time trend of the growth model, the oyster weight temporarily decreases owing to egg deposition. After egg deposition, the oyster grows again. The fi ltration rate of oyster increases rapidly with oyster growth and increasing temperature after early summer. The largest bloom of phytoplankton, which is the main diet of oyster, occurs from January to April. Therefore, we inferred that the oyster diet diminishes after early summer.