Evidence of Strong Lake Trout Recruitment Despite High PCB (Total Aroclors) Concentrations

Abstract

Lake trout in New York's Canadice Lake have exhibited strong natural recruitment despite total PCB concentrations four to seven times those recently found in lake trout from the Great Lakes. In contrast, lake trout recruitment has been significantly impacted in Lakes Ontario, Michigan, and Huron. This evidence is inconsistent with the hypothesis that PCBs caused the failure of lake trout recruitment in the Great Lakes over the last two decades. A limitation of this conclusion is that PCBs in Canadice Lake lake trout were quantitated only as total Aroclors. It is possible that Canadice Lake PCBs have a relatively low toxicity per unit PCB. On the other hand, in contrast to most data suggesting impacts of PCBs on recruitment, the Canadice Lake data are from a natural population in a natural system, and include the suite of natural biotic and abiotic factors, lethal and sub-lethal, affecting lake trout recruitment throughout the fish's life-cycle.