Acute and chronic nitrite toxicity in juvenile pike-perch (Sander lucioperca) and its compensation by chlorides

Pike-perch Sander lucioperca is currently considered as one of the most promising candidates for production in freshwater recirculation aquaculture systems (RAS). Here, due to the lack of studies on nitrite (NO(2)(-)) toxicity in pike-perch, a flow-through exposure at 0, 0.44, 0.88, 1.75, 3.5, 7, 14 and 28 mg/L NO(2)(-)-N was carried out to determine the acute and chronic toxicity over a period of 32 days. In juvenile pike-perch, 120 h LC(50) was 6.1mg/L NO(2)(-)-N and at ≥14 mg/L NO(2)(-)-N all fish had died within 24 h. Chronic exposure revealed a significant build up of NO(2)(-) in the plasma as well as in the muscles at ≥0.44 mg/L NO(2)(-)-N peaking in fish exposed to the highest concentration of 3.5 mg/L NO(2)(-)-N after 32 days. Still, due to high individual variation methemoglobin (MetHb) was only significantly increased (p