Study on the Effects of Ultrasonic Wave on Hatching of Fertilized Egg in Four Marine Fish

Effects of fixed frequency and intensity ultrasonic waves, with different radiation duration and times, on hatching of fertilized egg in Boleophthalmus pectinirostris (Linnaeus), Bostrichthys sinensis (Lacepede), Pagrosomus major (Temminck et Schlegel) and Pseudosciaena crocea (Richardson) were investigated. The results showed that ultrasonic radiation increased hatching rates of Boleophthalmus pectinirostris fertilized eggs for late developmental embryos, but it had negative effects on the hatching of Boleophthalmus pectinirostris and Bostrichthys sinensis fertilized eggs for early developmental embryos. Ultrasonic radiation, in 1 minute each time and 4 times total, was favorable to the hatching of Pagrosomus major fertilized eggs, whereas the hatching rates decreased if the radiation treatment duration was over 1 minute each time. Hatching rates of Pseudosciaena crocea fertilized eggs, treated with ultrasonic radiation in 10 s or 30 s each time, were 10% or 12% higher than that of the control.