Efficacy of Stocking Programs for Restoration of Coregonines: A Retrospective Analysis

Historically, coregonines were the principal prey fishes in the Great Lakes basin and provided forage to one of the largest Lake Trout populations in the world. The collapse of Cisco (Coregonis artedi) and the deepwater coregonines (C. spp.) across the Great Lakes during the 1920 - 1960s altered energy flow and predator-prey dynamics throughout the basin. With the reduction of non-native rainbow smelt and alewife populations across the Great Lakes, restoration of native coregonines through stocking is now being considered by management agencies. Several Great Lakes hatchery managers travelled to Finland in 2012 and 2014 to observe its large-scale coregonine broodstock and culture programs. To augment the knowledge gained from these trips, this study examined the efficacy of coregonine stocking programs in North America, Europe, and Asia.  Variables analyzed in relation to restoration successes were stocking strategy (e.g., size/age  at stocking, numbers released, gamete source) and the conditions of the receiving waters (e.g., size of waterbody, flow dynamics, and current fish community status). Professionals were surveyed for particular case study details. Based on the study’s findings, current culture and stocking protocols will be refined and adapted to provide the best opportunity to restore extirpated coregonines in the Great Lakes.