Effects of Using Semen of Green Spotted Scat (Scatophagus argus) and Red Spotted Scat (S.argus var. rubrifrons) for Artificial Insemination and the Larval Rearing and Salinity Tolerance of Pure Cross and Hybrid Larvae

Abstract

Effects of green spotted scat (Scatophagus argus Linnaeus, 1766) and red spotted scat (S. argus var. rubrifrons) semen on artificial insemination success, and larval rearing and salinity tolerance of pure cross and hybrid larvae were investigated in 3 experiments. Experiment 1: a comparative study of artificial insemination of green scat ovulated oocytes with green and red scat semen was conducted. The resultsshowed that fertilization rate (69.01±4.43 and 70.58±6.77 %), hatching rate (72.41±5.21 and 70.60±3.95%), total length of new hatch out larvae (1.75±0.05 and 1.80±0.10 mm.), number of hatch out larvae on weight of broodfish (481.77±229.78 and 523.30±236.79 g.) and survival rate of day 3 larvae (62.50±9.17and 62.50± 9.17%) were not significantly different (P>0.05). Experiment 2: a comparative study of the larval rearing between 2 stages (1-20 and 21-45 day old larvae) of pure cross and hybrid larvae was conducted. The results showed that wet weight, body depth, total length and survival rate of the larvae were not significantly different (P>0.05). Experiment 3: a comparative study of the tolerance to abrupt changes in salinity of 2 strains of larvae at 0, 15, 30 and 45 ppt was conducted. The results showed that their survival rates at all the salinities were not significantly different (P>0.05). This study indicated that different semen from green and red scat did not affect artificial insemination success, larval rearing performance and the salinity tolerance of the larvae. These findings may create opportunities in mass seed production of hybrid spotted scat larvae.