The effects of copper on maximum respiration rate and growth rate of perch, Perca fluviatilis L.

Addition of copper to the ambient water of perch resulted in decreased daily maximum respiration rates (R_max) and growth rates. The time-course of the effect in R_max was characterized by: (1) an initial decrease over three additions; (2) a minimal “trough” lasting some 10–15 days; and (3) a phase of increasing R_max. The variation in R_max was due to copper concentration and exposure time. The decrease in growth rate was most dramatic initially and was correlated to copper concentration and perch weight. The subsequent increase in growth rate was constant and independent of copper concentration. The increase in R_max and in growth rate was interpreted as acclimatization. Up to a given sublethal copper concentration acclimatization resulted in a return to the control level of R_max but not of growth rate.