Effects of Dam Removal & Habitat Restoration on Migratory Fishes of Green Bay with Emphasis on Northern Pike (Esox lucius)

Two dams on Duck Creek (Green Bay, Wisconsin) were removed in 2012. Removal opened several miles of potential spawning habitat for migratory fishes. However, the conversion of riparian habitat to agricultural or urbanized areas leaves the impact in question. The study objectives included: 1) determining how fish species composition and habitat use change after barrier removal, and 2) comparing northern pike recruitment success between restored and reference habitats. Larval box traps were used to quantify the number and size of larval fish out-migrating from Duck Creek (downstream and upstream of the dam removal site), as well as reference systems around Green Bay (13 sites). Larval fish captured were counted, measured, and released. Over two years, migratory fishes including white sucker and walleye were observed spawning upstream of the dam removal site and out-migrating larval white sucker were captured. More than 30 fish species were identified, including banded killifish, a WI species of concern. However, no larval northern pike were captured upstream of the dam removal site in contrast to reference locations. This research suggests while the dam removal can have a positive effect on the fish community, some migratory fish may not realize the added benefit without concurrent habitat restoration.