EFFECTS OF LOW pH ON BLOOD ACID-BASE BALANCE IN GRASS CARP (CTENOPHARYNGODON IDELLUS CURIER AND VALENCIENNES)
低pH对草鱼血液酸碱平衡的影响

Blood acid-base balance and partial pressure of O2 and CO2 were studied in grass carp (Ctenopharyngodon idellus) exposed to low environmental pH (6.0-4.0). The results showed that the fish suffered from severe acid aemia. At sublethal pH 6.0-5.0, the effect on blood acid-base balance appeared mainly on loss of blood bicarborate HCO3-] and apparent decrease in blood pH could be stabilized by buffer-regulating in organism.Other than a more substantial blood acid-base disturbance, anoxia also occured in grass carp at pH 4.0 for 96 h. It is suggested that grass carp is relatively-acid sensitive. In order to protect the survival and propagation of adult fish in natural water, pH should be kept above 6.0.