墨西哥湾扇贝稚贝盐度适应性的研究

在室内控制条件下,观察不同海水盐度对墨西哥湾扇贝(Argopecten irradians concentricusSay)稚贝存活及生长的影响,并将168 h 50%死亡的盐度作为适宜生存临界盐度,将增长率为最佳增长率30%时所对应的盐度作为适宜生长临界盐度。结果表明:在稚贝壳高4.38 mm±0.31 mm,水温25.4~27.8℃,pH值7.8~8.2下,墨西哥湾扇贝稚贝适宜生存盐度为23.6~35.7,最适生存盐度为26.0~31.3;适宜生长盐度为23.9~35.8,最适生长盐度为28.7~31.3。在盐度变化超出最适范围时,`墨西哥湾扇贝稚贝对低盐更为敏感,高盐比低盐对稚贝存活、生长、增重的影响小。当盐度为28.7时,墨西哥湾扇贝稚贝具有最高的相对存活率(100%)、壳高日增长率(0.116 2 mm.d-1)及体重日增长率(1.95 mg.d-1)。当盐度在最适范围之外升高或降低,稚贝的存活率、壳高及体重日增长率也随着降低。

Study on Adaptability of Juveniles of Argopecten irradians concentricus Say to Salinity

Effects of various seawater salinities on the growth and survival of juveniles of Argopecten irradians concentricus Say by adopting indoor control measures were investigated.The salinity ensuring mortality of 50% for 168 h as a period of experiment was chosen as the survival critical salinity,while the salinity in the group with 30% as much as the highest growth rate was set to be the growth-suitable critical salinity.Based on these critical salinities,the optimum salinity suitable for the juveniles of Argopecten irradians concentricus Say was studied.The results showed that when the juvenile shell height,water temperature and pH range is 4.38 mm±0.31 mm,25.4-27.8 ℃ and 7.8-8.2 respectively,the suitable survival salinity is 23.6-35.7,the optimum survival salinity is 26.0-31.3,the suitable growth salinity is 23.9-35.8,the optimum growth salinity is 28.7-31.3.Upon the change of salinity beyond optima,juveniles are more sensitive to low salinity,high salinity is more desirable for the survival,growth as well as body increment.When salinity amounts to 28.7,juveniles of Argopecten irradians concentricus Say has the highest relative survival rate(100%),shell height daily gain is 0.116 2 mm·d~(-1),body weight daily gain is 1.95 mg·d~(-1).When salinity is higher or lower than that out of the optimum range,survival rate,shell and body weight daily gains drop accordingly.