温度和盐度对长牡蛎“海大1号”二倍体和三倍体幼虫生长与存活的影响

Effects of Temperature and Salinity on the Growth and Survival of Diploid and Triploid Larvae of Pacific Oyster “Haida No. 1”

为确定长牡蛎(Crassostrea gigas)“海大1号”苗种规模化繁育的最适条件,本研究设置4个温度梯度(20、25、30和35℃)和5个盐度梯度(20、25、30、35和40),分析了不同温度和盐度对长牡蛎“海大1号”二倍体和三倍体幼虫生长和存活的影响。研究表明,当温度25℃和盐度30时,长牡蛎“海大1号”二倍体和三倍体幼虫的受精率、孵化率和变态率最高。不同温度处理下,三倍体幼虫的生长速度和累计存活率始终高于二倍体幼虫。随着温度升高幼虫生长速度增加,但存活率下降,在25℃时三倍体幼虫存活率最高(52.00%±6.56%),温度为30℃时,三倍体幼虫壳高增长最快(14.82μm·d^(-1))。不同盐度下,三倍体幼虫的生长速度和累计存活率显著高于二倍体幼虫。幼虫的存活率随着盐度升高呈先升高再下降的趋势,三倍体幼虫累计存活率在盐度30时最高(52.00%±6.56%);幼虫的生长速度随着盐度升高呈下降的趋势,三倍体幼虫壳高在盐度20时增长最快(18.22μm·d^(-1))。研究结果表明,长牡蛎“海大1号”三倍体幼虫比二倍体幼虫表现出更强的温度、盐度的耐受性;长牡蛎“海大1号”三倍体苗种培育的适宜盐度为20~30,适宜温度为20~25℃。本文可为长牡蛎“海大1号”三倍体苗种的规模化繁育提供参考。

In order to promote the development of the triploid industry of an excellent variety of Pacific oyster Crassostrea gigas“Haida No.1”,and optimize its rearing conditions and improve the survival and growth rate,the effects of different temperatures and salinities on the growth and survival of diploid and triploid larvae were investigated.Four temperatures(20,25,30 and 35℃)and five salinities(20,25,30,35 and 40)were set up for the experiments.The highest fertilization,hatching and metamorphosis rates of thediploid and triploid larvae of Pacific oyster“Haida No.1”were found when the temperature was 25℃and salinity was 30.At different salinities,the growth and cumulative survival rates of triploid larvae were significantly higher than those of diploid larvae.The growth and cumulative survival rates of triploid larvae were consistently higher than those of diploid larvae at different temperatures.The survival rate of triploid larvae decreased with temperature,reaching the highest at 25℃(52.00%±6.56%).The fastest growth in shell height of triploid larvae was observed at 30℃(14.82μm·d^(-1)).The survival rate of triploid larvae increasfirst and then decreased with increasing salinity,and the cumulative survival rate of triploid larvae was highest at 30(52.00%±6.56%).The growth rate of larvae decreased with increasing salinity,and the shell height of triploid larvae grew fastest at 20(18.22μm·d^(-1)).In conclusion,the triploid larvae of Pacific oyster“Haida No.1”showed stronger temperature and salinity tolerances than the diploid larvae.The optimum salinity for the cultivation of triploid Pacific oyster“Haida No.1”ranged from 20 to 30 with the most suitable varied between 20 and 25℃.Our findings provided important information for the large-scale breeding of the triploid seeds of Pacific oyster“Haida No.1”.