Study on temperature and salinity tolerance of juvenile Scapharca subcrenata

Background The temperature and salinity tolerance of juvenile Scapharca subcrenata was evaluated under controlled laboratory conditions.

Methods Experimental research and data analysis were performed using ANOVA and Duncan’s multiple range test, among other approaches.The experiment used juvenile S. subcrenata as the research subject.Under conditions of dissolved oxygen (DO) ≥ 5 mg/L and pH 8.0–8.5, the temperature tolerance experiment was conducted with five low-temperature groups (6, 8, 10, 12 and 14 ℃), five high-temperature groups (30, 32, 34, 36 and 38 ℃), and one control group maintained at a normal water temperature of 25 ℃. For the salinity tolerance experiment, 11 salinity levels were set: 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, and 39, with salinity 27 serving as the control.

Results 1) In the temperature tolerance experiment: low temperatures of 6–10 ℃ imposed significant survival stress on juvenile S. subcrenata ( at the end of the experiment, relative survival rates at 12 ℃, 14 ℃ , and 30 ℃ were 2.00%, 12.00%, and 35.33%, respectively). Survival remained high in the range of 12–30 ℃ (at the end of the experiment, relative survival rates at 12 ℃, 14 ℃ , and 30 ℃ were 54.00%, 70.00%, and 73.33%, respectively). High temperatures of 32–38 ℃ caused severe damage to juvenile S. subcrenata, with total mortality observed at 9, 6, and 5 days, respectively. Under temperature stress, the low-lethal temperatures (LT₅₀) for juvenile S. subcrenata at 48 h, 96 h, 144 h, and 192 h were 4.92 ℃, 4.70 ℃, 7.14 ℃, and 9.50 ℃; the corresponding high-lethal temperatures (UT₅₀) were 37.48 ℃, 33.49 ℃, 32.66 ℃, and 31.71 ℃, respectively. 2) In the salinity tolerance experiment, the low-salinity lethal levels (LS₅₀) for juvenile S. subcrenata at 48 h, 96 h, 144 h, and 192 h were 10.00, 13.33, 15.63, and 15.79; the high-salinity lethal levels (HS₅₀) were 40.83, 37.95, 36.31, and 35.69. The suitable salinity range for juvenile S. subcrenata survival was 16.30–35.26, the preferable range was 17.80–35.04, and the optimal range was 24.00–30.00. For juvenile S. subcrenata growth, the suitable salinity range was 15.69–36.10, the preferable range was 24.60–30.00, and the optimal range was 24–27.

Conclusion The results of this study indicate that juvenile S. subcrenata have higher tolerance to low temperature than that to high temperature, making them more suitable for aquaculture in northern China. They are euryhaline shellfish that can be cultured in both ponds and tidal flats.In the seedling rearing and aquaculture of juvenile S. subcrenata, marine areas with water temperature of 14–30 ℃ and salinity of 24–30 should be prioritized, where water temperature and salinity are relatively stable without sudden fluctuations. The study provides data support for the propagation and aquaculture of juvenile S. subcrenata in northern China, and effectively promotes the industrial development and resource restoration of native shellfish.