Characterization and inhibition of nitrite uptake in shortnose sturgeon fingerlings

Efforts are underway to culture the endangered shortnose sturgeon Acipenser brevirostrum for possible reintroduction. As part of a larger project to develop culture techniques for this species, the uptake of nitrite was evaluated in fingerlings (16.5 ± 4.85 g; mean ± SD). Plasma nitrite concentrations increased significantly with exposure time (0–5 d) and dose (0–4 mg nitrite-N/L). Shortnose sturgeon fingerlings were able to concentrate nitrite in their plasma to more than 63 times the environmental concentration. Chloride, as either sodium chloride or calcium chloride, partially inhibited nitrite uptake. However, calcium chloride was a better inhibitor. After previous exposure (2 d at 2.13 ± 0.080 mg nitrite-N/L) plasma nitrite-N decreased from 165.5 to 36.7 mg/L during a 3-d simultaneous exposure to 2.13 ± 0.080 mg nitrite-N/L and treatment with 40 mg chloride/L as calcium chloride. The addition of calcium chloride to the water appeared to be an effective means of preventing nitrite uptake and treating nitrite toxicity in hatchery-reared shortnose sturgeon fingerlings.