Tolerance, Growth, and Physiological Responses of the Juvenile Razor Clam (Sinonovacula constricta) to Environmental Ca2+ and Mg2+ Concentrations

To facilitate transplanting razor clam ( Sinonovacula constricta ) populations to inland saline-alkaline waters (ISWs), we evaluated the tolerance of juvenile S. constricta (JSC) to Ca 2+ and Mg 2+ concentrations, and determined the effects of these ions on JSC growth and physiological parameters. After 30 days stress, the tolerable ranges of JSC to Ca 2+ and Mg 2+ were determined to be 0.19 mmol⋅L -1 –19.46 mmol⋅L -1 and 0 mmol⋅L -1 –29.54 mmol⋅L -1 , respectively. The concentrations of Ca 2+ (less than 0.65 mmol⋅L -1 or more than 3.24 mmol⋅L -1 ) and Mg 2+ (less than 0.37 mmol⋅L -1 or more than 14.17 mmol⋅L -1 ) significantly inhibit JSC growth. Physiological enzyme activity no significant response when the concentrations range of Ca 2+ and Mg 2+ are 0.93 mmol⋅L -1 –6.49 mmol⋅L -1 and 0.37 mmol⋅L -1 –14.77 mmol⋅L -1 , respectively. For transplantation practice, these data indicate that only high concentrations of Ca 2+ (3.24–6.825 mmol⋅L -1 ) and Mg 2+ (14.77–33.69 mmol⋅L -1 ) in target inland saline-alkaline water had significantly impact on growth and physiological response. In addition, present study suggests that the increase in Ca 2+ and Mg 2+ ion concentrations caused by ocean acidification will not affect the survival, growth and physiology of S. constricta . Current research suggests that S. constricta can adapt to extreme changes in the marine environment (Ca 2+ and Mg 2+ ) and may be an excellent candidate for inland saline-alkaline water transplantation practice.