Growth, oxygen consumption, ammonia excretion, feeding and assimilation rate were examined from May 2010 to February 2011 in order to assess the physiological changes of Haliotis discus hannai in accordance with changes in season. The water temperature was in the range of 8-23.2℃ and the salinity in the range of 31.9-34.1psu during the examination period. The length of shell of Haliotis discus hannai grew from 36.3 mm to 66.1 mm in the 1 year old entities and from 60.6 mm to 66.1 mm for the 2 year old entities, while the weight of the meat increased from 3.16 g to 12.04 g and from 15.8 g to 21.5 g, respectively. The oxygen consumption and ammonia excretion rate displayed trend of increase in accordance with the increase in water temperature, while the feeding rate was high during the period from July to October. The assimilation rate was in the range of 68%-71% without significant difference between the age of the entities and seasons. SFG displayed +value throughout the year for the 1 year old entities of Haliotis discus hannai as well as for the 2 year old entities with the exception of the period of July, thereby showing that they are growing throughout the year. Therefore, there was no environmental effect including water temperature and salinity during the examination period.
