Salinity tolerance of embryos of obscure puffer Takifugu obscurus

Abstract

Salinity tolerance of embryos of obscure puffer Takifugu obscurus was investigated at salinities of 0, 4, 8, 12, 16, 20, 24, 28, and 32 parts per thousand (ppt), respectively. Survival rates of embryos at 0, 4 and 8 ppt salinities were higher than 90% throughout the experiment, and there were no significant differences between 0 and 8 ppt ( P > 0.05), whereas most embryos died gradually at salinity of 12 ppt or higher after four days. Total hatch rates at 0, 4, and 8 ppt were 95.0%, 95.0%, and 91.0%, respectively. A few embryos hatched at salinities of 12, 16, 20, and 28 ppt; however, all larvae were deformed and died in 24 h post-hatch. Only at salinity of 8.0 ppt or lower, the embryos hatched into viable larvae. Hatching period at 0, 4, and 8 were 171, 182, and 182 h, respectively. Within the tolerable salinity range (0–8 ppt), there were no significant differences in total hatch rates, viability of 24 h post-hatch larvae, and rate of embryonic development ( P > 0.05). We concluded that embryos of obscure puffer could not tolerate salinities of 12 ppt and higher, but could well adapt to salinities below 8 ppt. Thus, it is viable to incubate embryos of obscure puffer under lower salinity conditions.