Effects of photoperiod, temperature, and salinity on growth and survival of obscure puffer Takifugu obscurus larvae

The effects of photoperiod, temperature, and salinity on growth and survival of obscure puffer Takifugu obscurus larvae were determined from 3 to 19 days after hatching (dah). The results showed that the optimal photoperiod for obscure puffer larvae was under continuous light conditions (24 h light:0 h dark). Increasing daylength resulted in improved larval growth and survival. Larvae cultured under total darkness grew very slowly and even negatively, and all died within 12 days (15 dah). The optimal and critical high temperatures for obscure puffer larvae were at 22–23 and 32 °C, respectively. The specific growth rates (SGR) of obscure puffer larvae increased with an increase in temperature from 20 to 29 °C, while no corresponding increase in SGR was observed for temperatures from 29 to 32 °C. Larval survival rate significantly decreased when the temperature increased from 23 to 32 °C, and there was a tendency for a low survival rate at 20 °C. A high salinity (25‰) resulted in reduced larval growth and survival probabilities. The highest survival and specific growth rates were both predicted to occur at 8‰ to 10‰ based on quadratic equations. High SGR (5.71–6.14% d− 1) and survival rates (> 90%) were found within a wide salinity range (0–20‰). The optimal and suitable salinity ranges of larviculture were 8–10‰ and 0–20‰, respectively. Therefore, obscure puffer larvae can feasibly be cultured in brackish water (0–20‰) existing in majority of coastal areas.