Water quality criteria (WQC) for the protection of aquatic life have not explicitly considered the degree of protection afforded to aquatic species listed as endangered or threatened under the U.S. Endangered Species Act (listed species). Most WQCs are based primarily on responses of a limited number of surrogate species, which are easily cultured and tested in the laboratory. Little information is available about the relative sensitivity of listed species to toxic chemicals, especially with respect to chronic toxicity. We conducted a series of chronic, early-life-stage toxicity tests with two listed species, fountain darter (Etheostoma fonticola) and spotfin chub (Cyprinella monacha), and two surrogate species, fathead minnow (Pimephales promelas) and rainbow trout (Oncorhynchus mykiss), exposed to copper (Cu).

Includes bibliographical references (pages 10-11 (first group)).