BLOOD RESPIRATORY CHANGES IN COMMON CARP EXPOSED TO A LETHAL CONCENTRATION OF ROTENONE

Common carp Cyprinus carpio were exposed to a lethal concentration of rotenone (0.1 mg/L), and blood was sampled after 2, 7, and 21 min. Exp osure times were selected to correspond with changes in behavior: afte r 2 min fish started swimming to the surface, after 7 min equilibrium was lost, and after 21 min fish sank to the bottom. Fish died 35-40 mi n after exposure to rotenone. Blood oxygen partial pressure showed a d ramatic 10-fold increase compared with control values after 21 min, wh ile pH decreased and partial pressure of carbon dioxide did not change . Increases in blood oxygen content, which were probably related to bl ockage of cellular oxygen use, indicate that branchial uptake of oxyge n was not significantly impaired.