Acute copper poisoning of cultured marine teleosts

Copper was accidentally introduced into seawater entering a circular outdoor tank used to culture 610 pinfish (Lagodon rhomboides) and other marine teleosts. Fish were exposed for 23 hours to copper concentrations between 0.2 parts per million (ppm) and 7.2 ppm with an average concentration of 3.3 ppm. The pinfish were lethergic by 6 hours after copper was introduced into the tank. Deaths began within 10 hours with a total of 575 (94%) deaths. Deaths stopped 11 hours after copper concentrations decreased below 0.2 ppm and signs of distress stopped in surviving pinfish by approximately 6 hours after the last death. Serum urea nitrogen, alkaline phosphatase, sodium (Na+), and potassium (K+) concentrations were increased and represent those constitutents which differ from mean control values by more than 2 standard deviations. Electrolyte imbalance, apparently resulting from impaired osmoregulation and hemolysis, was a serious terminal condition in copper-poisoned pinfish.