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

The Menominee River currently supports some of the largest stocks of lake sturgeon associated with the Great Lakes, including the section of river between White Rapids and Grand Rapids dams (i.e., White Rapids section). Current management activities include sampling to determine the status of lake sturgeon in the White Rapids section of the river and to capture fish for collection of gametes that will be used in propagation. The inability of biologists to identify sex and maturation status in a nonlethal manner complicates lake sturgeon management and research activities that occur on this and other sections of the river. Specifically, biologists often guess at population sex ratios and they also encounter difficulty in selecting fish for collection of gametes used in propagation or for ongoing research regarding fish passage through or around hydroelectric facilities. Additionally, the potential effects of harvest regulations and future fish passage on lake sturgeon in the White Rapids section and other portions of the Menominee River requires estimates of population sex ratios and the maturation status of adult fish. Consequently, lake sturgeon management and research activities would be greatly enhanced if sex and maturation status can be more accurately determined. Portable ultrasound technology offers a rapid, non-invasive method that can be used to determine the sex and maturation status of several sturgeon species, including lake sturgeon. Our objective is to use a portable ultrasound to determine the sex and maturation status of lake sturgeon in order to improve lake sturgeon assessment, management, and research activities in the White Rapids section and other portions of the Menominee River. Specifically, we will combine the use of passive integrated transponder (PIT) technology with the ultrasound which will allow biologists to better determine population sex ratios and maturation history of individual lake sturgeon. We will develop a reference guide to help biologists determine the sex and maturation status of lake sturgeon from ultrasound images.