Considering aquatic connectivity trade-offs in Great Lakes barrier removal decisions

Globally, construction of dams has led to challenges for fishery managers and decision makers. Hundreds of thousands of dams, many of which no longer serve their intended purpose, are in need of repair. Resources to make those repairs are limited, and dam removal often seems like the most logical solution from an economic perspective. However, dams on the Laurentian Great Lakes tributaries often serve more than one purpose, with nearly 500 considered important to the continued success of controlling sea lamprey (Petromyzon marinus), blocking other invasive species, isolating native from non-native salmonids, stopping disease transfer, and holding back contaminated sediments. Removing dams can have unintended consequences at the local, regional, or basin-wide scale. Here, we explain the importance of considering potential fishery management trade-offs of barrier removals at those scales. We also suggest an organizational framework that, when supported by modeling, could improve communication and cooperation among partners, streamline the decision process, and provide a consensus-driven perspective about the highest priority projects to address. Consistent communication among and between management agencies, indigenous peoples, and local governments, along with an objective and proactive approach to barrier removal decisions could allow for greater success in habitat restoration and funding procurement while reducing the risk of barrier failures and the unintended spread of injurious invasive species, environmental contaminants, and fish disease. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of International Association for Great Lakes Research. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Construction and maintenance of dams globally pose challenges for fishery management, with many dams in need of repair or removal due to economic constraints. However, the multifunctional nature of dams in certain regions warrants careful consideration, as removal could have unintended consequences.