If all chicks that are at risk for toxicity within the assessment region die before transition to adult stage (a conservative assumption), then reductions in Hg emissions to levels that result in Hg concentrations in loon prey ,0.08 mg kg1 wet weight ( loon chick NOAEL from dosing study) should increase juvenile survival by 10%; and hatching success could be increased by 30% in 10% of the reproducing females.