Effect of high temperature stress on growth and survival of juvenile Haliotis discus hannai Ino

To study the tolerance of juvenile Haliotis discus hannai Ino to high temperature, we designed five groupswith three parallels each. The temperature of control group was set as natural temperature, and that of the other four groups were set as 25 ℃, 28 ℃, 31 ℃ and 32 ℃, respectively, so as to analyze the growth and mortality of each group. In the 45-day experiment, the mortalities of Group A~E were 2.2%, 11.1%, 43.3%, 81.1% and 86.7%, respectively; growth rates of shell length were 1.2%, 0.5%, 0.3%, 0.1% and 0.1%, respecitively; growth rates of shell width were 1.2%, 0.6%, 0.3%, 0.1% and 0.1%, respectively; growth rates of wet weight were 6.6%, 3.3%, 1.7%, 1.1% and 1.2%, respectively. The results indicate that when the temperature was higher than the optimum temperature, the mortality of juvenile abalones increased and grew slowly as the temperature increased. It is concluded that the tolerance to high temperature of juvenile H.discus hannai Ino might beabove 30 ℃.