Reciprocal influences of temperature and copper on survival of fathead minnows, Pimephales promelas

Influences of temperature and copper concentration on the survival of Pimephales promelas (fathead minnow) were investigated. Chemicals were known to influence the temperature tolerance of fish, while temperature also affected the sensitivity of fish to toxic chemicals. The relationship between these factors was complex and not adequately understood. The acclimation temperature significantly affected the 96 h median lethal concentration of copper in fathead minnows. Copper was lethal in the ug per litre range. A quadratic relationship was hypothesized between acclimation temperature and copper lethality. Exposure to copper also adversely affected the ability of fish to withstand high temperatures.