Oncorhynchus mykiss escaped from commercial freshwater aquaculture pens in Lake Huron, Canada

Abstract

The fate of farmed fish after escape from aquaculture operations, and their potential ecosystem impacts, remains a primary concern for the sustainable development of this industry. We simulated small- (350 km), where they were located in rivers, open waters and in an adjacent Great Lake. Rainbow trout maintained high specific growth rates (average 0.33% d-1) in the wild, both at and away from the farms. Known survival of escaped fish after a 3 mo period following release was ~50%, with some fish recaptured up to ~2.5 yr after release. Angling and avian predation accounted for the majority of mortalities. The ability of farmed fish to survive, successfully forage near and far from aquaculture operations and their preponderance to occupy near-shore habitats provide a strong basis for understanding the potential risks that escaped fish may pose to the fish community of Lake Huron.