At the outset of AOSERP there was considerable concern that significant quantities of acid precipitation and heavy metals emanating from oil sands plants might adversely affect lakes near the oil sands area. Thus, the Aquatic Fauna Technical Research Committee initiated this project with the objectives to determine: 1) if acid fallout lowers the overall productivity of lakes; 2) if acidification directly affects the physiology of fishes, their eggs or fry; and 3) if heavy metals deposited in the lakes or mobilized from sediments are toxic to fishes or their food organisms. These objectives were addressed by the researchers in a whole lake experiment at the Experimental Lakes Area in northwestern Ontario because of the experimental control that could be effected at the facilities. A complementary project directly concerning lakes adjacent to the oil sands region has been conducted. For further infonnation the reader is referred to AOSERP Report No. 71, entitled \"Lake Acidification Potential in the AOSERP Study Area\".