A series of experiments was conducted during the spring, summer and fall of 1977 to determine the potential copper toxicity hazard to Babine Lake sockeye salmon (Oncorhynchus nerka) fry, lake fingerlings and smolts. Acute 96 h LC50's were determined for the three life stages utilizing static bioassays with 24 h solution replacement and CuC12·2H20 as a toxicant in on-site testing using natural lake water. 96-h LC50 values complete with 95% confidence limits were obtained for fry, fingerlings and smolts and ranged from 210-220 μg Cu++/L for fry, to 240 μg Cu++/L for smolts and lake fingerlings expressed as total copper concentration as measured in test solutions. It was concluded that the present low levels of copper in the lake (4-44 μg/L total Cu++), coupled with the considerable complexing capacity of Babine Lake water (in excess of 100 μg Cu++/L), pose no acute toxicity threat to Babine sockeye at this time.