Assessing the post-stocking survival, predation, and movements of cisco in Lake Erie

Contributing Authors

Project Description

Cisco (Coregonus artedi) were once an ecologically and culturally important native prey fish in Lake Erie and supported one of the most valuable freshwater fisheries on earth, but overfishing caused the fishery to collapse by 1925. Cisco were observed only rarely in Lake Erie through the 1950s and are now considered extirpated from the lake. In 2025, an experimental cisco reintroduction effort was initiated in the New York waters of Lake Erie, with stocking planned to continue for up to 10 years. Re-establishing cisco could help restore a historically important coregonine to the Lake Erie fish community and provide forage for native predators such as walleye, lake trout, and muskellunge. However, the success of reintroduction will depend on understanding the fate of stocked fish after release, including early survival, predation risk, movement away from stocking sites, and habitat use. This project will use acoustic telemetry to evaluate the post-stocking survival, predation, and movements of juvenile cisco released into Lake Erie. In 2025 and 2026, juvenile ciscoes were tagged with Innovasea V7D predation detection acoustic transmitters and released as a subset of the broader reintroduction effort. The tagged subset included 71 fish in 2025 and 80 fish in 2026. The V7D acoustic transmitters have an expected battery life of 227 days, allowing fish to be tracked for up to approximately 7.5 months after release. To monitor these fish, the project will deploy a fine-scale acoustic receiver array near Dunkirk, New York, consisting of 100 receivers spaced approximately 2 km apart. Tagged cisco will be released across nearshore and offshore stocking locations to determine how release methods influence short-term survival, predator interactions, dispersal, and habitat use. By identifying factors that influence early survival, predation, dispersal, and spatiotemporal habitat use, this project will help managers evaluate whether stocked cisco survive long enough to contribute to reintroduction goals, identify release locations and conditions that may improve post-stocking outcomes, and determine whether early predation represents a bottleneck to restoration success. Acoustic telemetry will also help identify when and where future sampling should occur. By combining detections from the Dunkirk receiver array with partner detection data from GLATOS, this work will support adaptive management of the 10-year reintroduction effort and provide fisheries managers with information needed to refine future stocking and assessment strategies for cisco restoration in Lake Erie.