Resistance Board Weir – a Versatile Fisheries Management Tool with Applications Worldwide

For decades, fisheries managers have struggled with ways to successfully capture, enumerate, segregate, and even block migrations of anadromous fish into rivers and watersheds.  In recent years, resistance board weirs have been used on rivers and streams to effectively manage and sample migratory fish populations.  Resistance board weirs are currently in use throughout the Pacific Northwest of North America; however, fishery managers outside of this area are also starting to explore ways to utilize the technology to address region-specific fishery questions and sample their species of interest.

We describe the basic structure and function of a resistance board weir, its current use throughout the Pacific Northwest, and review a recent case study located in western Norway.  The project’s main species of interest is the Atlantic salmon (Salmo salar) with a goal of removing farm-raised escapees from the wild spawning population.  During the first season of operation the weir successfully removed a total of 92% of returning farmed salmon escapees from the river.  In addition, we will discuss the potential to incorporate recent advances in fisheries science into the resistance board weir structure, such as high definition video, spot pattern recognition and genetic sampling analysis.