Abstract Objective Investigate the effects of salinity on the spawning of Channel Catfish Ictalurus punctatus broodstock in the saline waters of coastal Jiangsu, China. Methods The study established five salinity gradients (0, 1, 3, 5, and 7‰) and systematically compared cumulative spawning rate, spawning time, spawn weight, and egg diameter under different salinity conditions. The broodstock were acclimatized to the target salinity for 24 h in fiber-reinforced plastic tanks before being transferred to the spawning cylinder. Males and females were allowed to spawn volitionally. Results Salinity substantially affected the spawning process. In the control group (0‰) and low salinity groups (1‰ and 3‰), the cumulative spawning rate ranged from 60% to 80% and days to spawn were completed within 1 week. At 5‰ salinity, the cumulative spawning rate remained 60%, while days to spawn extended to 7.5 ± 5.9 d. When salinity increased to 7‰, the cumulative spawning rate was only 40% and days to spawn reached 8.3 ± 5.3 d. Egg masses exhibited gradual de-adhesion and loose morphology, eventually failing to maintain an intact matrix structure as salinity increased. Egg diameter significantly decreased and showed a significant negative correlation with salinity. Salinity showed a significant positive correlation with days to spawn and significant negative correlations with cumulative spawning rate and egg diameter. Conclusions Salinities at or below 3‰ have no adverse effects on Channel Catfish spawning, whereas salinities exceeding 5‰ severely inhibit reproductive performance. It is recommended that spawning farms for Channel Catfish be established in coastal Jiangsu waters with salinity ≤4‰. These results provide guidance for local fry production, support the establishment of a complete industrial chain for Channel Catfish in Jiangsu, and contribute to the sustainable development of the industry.
Cai et al. (Mon,) studied this question.