Cooperative Fish and Wildlife Research Units Program: Minnesota
Education, Research and Technical Assistance for Managing Our Natural Resources

Cisco populations have declined in Lake Superior, and Wisconsin recently implemented a harvest quota based onbiomass estimates from hydroacoustic surveys. Cisco are an important link between trophic levels, they link the lower (zooplankton) to the upper (lake trout) trophic levels. Decline in cisco could havenegative consequences on lake whitefish and other near shore fish, because the eggs of cisco are animportant part of their diets. Understanding movement and habitat use could help determine reasons fordeclines and improve ability to estimate population size and determine allowable harvest. This is a project led by Wisconsin Department of Natural Resources with scientists at Minnesota Cooperative Fish and Wildlife Research Unit playing a cooperative role. Hydroacoustics technology hasbeen used to estimate density of spawning cisco in Wisconsin waters of Lake Superior consistently since 2015, hydroacoustics data will be used to try and identify habitat areas that can be prioritized for protection and restoration. Further, the movement of cisco during spawning will beused to refine habitat use. Combining current research, assessment data, and harvest data could allow thefor management to develop a population model to better inform management.