Influence of Nitrite and Chloride Concentrations on Survival and Hematological Profiles of Striped Bass

Abstract

The 24-h median lethal concentration of nitrite (NO2–) for striped bass Morone saxatilis was 163 mg/L in static toxicity tests. Exogenous chloride ions increased the tolerance of the fish for NO2–; CaCl2 was more than twice as effective as NaCl. Plasma NO2–, cortisol, and methemoglobin were correlated positively with environmental NO2–. Plasma NO2– and methemoglobin were correlated negatively with environmental Cl–, but cortisol was not reduced by the presence of environmental Cl–. Striped bass maintained NO2– in the plasma (0–45 mg NO2–/L) at concentrations below those in the environment (0–250 mg NO2–/L). However, striped bass were sensitive to NO2– that entered the plasma; methemoglobin levels greater than 60% and plasma NO2–, levels greater than 70 mg/L resulted in significant mortalities.