盐度对虎斑乌贼(Sepia pharaonis)受精卵孵化及幼体活力的影响

Effects of Salinity on Fertilized Egg Hatch and Survival Activity Index of the Larvae of Sepia pharaonis

水温22±1℃条件下,研究不同盐度（15.0、18.0、21.0、24.0、27.0、30.0、33.0）对虎斑乌贼（Sepia pharaonis）受精卵孵化及幼体活力的影响。结果表明,受精卵孵化适宜盐度范围为27.0~33.0,最适盐度范围为30.0~33.0,随着盐度增加,培育周期和孵化周期呈逐渐缩短趋势,而孵化率则呈先升后降趋势。盐度15.0环境中,初孵幼体经24h累计死亡率为100%;盐度18.0、21.0中,24h的累计死亡率分别为4.15%和5.83%,不投饵存活8d和9d;盐度24.0~33.0中,24h幼体累计死亡率均为0,不投饵存活9~10d。随着盐度的增加,幼体的不投饵存活系数（SAI值）先升后降,在盐度30.0时达到最大值,盐度（y）与SAI值（x）间的函数关系可表示为：y=-0.1764x2＋9.807 9x-104.33（r2=0.927 8）。

The effects of salinities（15.0,18.0,21.0,24.0,27.0,30.0 and 33.0） on fertilized egg hatching and survival activity index（SAI） of the larvae of sepia pharaonis were studied in the laboratory at 22± 1℃.Results showed that the suitable salinity for hatching ranged from 27.0 to 33.0 and the optimum salinity was from 30.0 to 33.0.With the increase of salinity,the rearing and hatching periods decreased while the hatching rate increased first and then decreased.At salinity 15,newly hatched larvae cumulative mortality rate was 100% in 24h,while at salinity 18.0 and 21.0,cumulative mortality rate were 4.15% and 5.83%,respectively,and the newly hatched larvae can survive without feeding for 8-9 days.At salinity of 24.0-33.0,larval cumulative mortality rate was zero,and individual death emerged 3 days after hatching.newly hatched larvae could survive for 8-10 days without feeding.Similar to the trend of hatching rate,SAI increased with the increases in salinity,maximized at 30.0,and then decreased,and the relationship of SAI（x） against salinity（y） can be represented by a quadratic equation： y=-0.1764x2＋9.807 9x-104.33（r2=0.927 8）.