Comparison of salinity tolerance of newly hatched larvae of Pseudosciaena croceaand hybrid F1 of Pseudosciaena crocea (♀) ×Miichthys miiuy (（♂）)

Abstract:

The effects of salinity on the survivial of newly hatched larvae of Pseudosciaena crocea and the hybrid F₁ of Pseudosciaena crocea (♀) × Miichthys miiuy (（♂）) were investigated. The newly hatched larvae were transferred from sea water (salinity 27) to other seven salinities (12, 17, 22, 27, 32, 37, 42). The results showed that the survival rate, mean survival time (MST) and survival activial index (SAI) of the newly hatched larvae of large yellow croaker and hybrid F₁are decreased following the increase of salinity. In the salinity range of 12 to 32, the SAI values of hybrid F₁ was up to 62.42 to 86.56 which was significantly higher than the large yellow croaker (46.18 to 53.89). At the salinity 12, the MSTof large yellow croaker and hybrid F₁ reached the maximum value，（10.69±0.16） d and （13.47±0.35） d , and at the salinity 42, the MST reached a minimum value， (4.91±0.27） d and （6.30±0.27） d. The continued downward trend of survival rate, median death time (DT₅₀), mean survival time (MST) and survival activial index (SAI) of the newly hatched larvae of large yellow croaker and hybrid F1 were compared at the same salinity. The results show that the newly hatched larvae of hybrid F₁ had stronger ability to survive during salinity changes, and showed strong heterosis.