Upper Midwest Environmental Sciences Center
Lake sturgeon (Acipenser fulvescens) are listed as endangered or as a species of concern by most states along the Upper Mississippi River. Dams and other structures built to aid commercial navigation may hinder recovery of lake sturgeon populations. Because little is known about the effects of navigation on lake sturgeon in large rivers, the U.S. Fish and Wildlife Service has identified this as a priority research need.
This need for information is even more critical given proposed changes by the U.S. Army Corps of Engineers for increased barge traffic. Our study was designed to identify and describe habitat use and movements of lake sturgeon in the Upper Mississippi River, particularly in relation to navigation structures and commercial barge traffic.
Transmitters were implanted into a total of 31 lake sturgeon from two sites in the Upper Mississippi River (see map) to describe their habitats and movements. For both groups of lake sturgeon, the areas surrounding the tagging sites were heavily used (about 50% of locations by group) and frequently returned to after prolonged absences during the 18-month study. Silt-sand bottoms and flow were shared characteristic of these core areas and likely provide optimal conditions for common prey items of lake sturgeon. Minimal geographical overlap in range occurred between the two groups (see map), suggesting that river reaches and associated core areas were unique to groups or substocks of fish. Lake sturgeon exhibited complex movement behaviors and had ranges of 2 to 122 miles (average = 35 miles) during the study. Radio-tagged fish moved downstream and upstream through Upper Mississippi River navigation dams a total of 54 times. However, these dams appeared to be intermittent barriers to upstream passage with apparent restrictions during low to moderate flow conditions as compared to high flow conditions. Extensive use of the Wisconsin River by one group of lake sturgeon tagged in the Upper Mississippi River near Prairie du Chien, Wisconsin, has implications regarding management of a threatened population transcending regulatory boundaries. For example, two egg-carrying female lake sturgeon radio-tagged in the Upper Mississippi River where they are protected were harvested in the Wisconsin River during the fall fishing season. Our study indicates that lake sturgeon in the Upper Mississippi River System share many movement and habitat use characteristics with populations in other systems. However, significant data gaps preclude development of cogent management strategies, including information on population numbers and dynamics, identification of spawning areas, relations between groups, and assessment of the effects of commercial navigation.
This project was completed in September 2000.
For more information, see the below publication:
Knights, B. C., J. M. Vallazza, S. J. Zigler, and M. R. Dewey. 2002.
Habitat and movement of lake sturgeon in the Upper Mississippi River System,
USA. Transactions of the American Fisheries Society 131:507-522.
Principal Investigator: Brent Knights