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STURGEON STUDY PROGRESS REPORT- (Submitted by Brent Knights of the Upper Midwest Environmental Sciences Center). During summer 1997 and spring 1998, twenty-eight lake sturgeon in two navigation pools of the Upper Mississippi River were implanted with radio and ultrasonic transmitters. Seventeen lake sturgeon were tagged in a secondary channel in Pool 10 near Prairie du Chien, WI; eleven sturgeon were tagged 155 km upstream in an off-channel area of Pool 5a near Winona, MN. Tagged lake sturgeon ranged from 94 to 152 cm in length and from 7 to 26 kg in weight. Lake sturgeon were located weekly to determine habitat use and movement. Additionally, lake sturgeon found in or near the main navigation channel during weekly tracking were more intensively tracked for up to one hour before and after commercial barge passage to determine their response. Tracking was completed during December 1998 and data analysis is currently underway. Data from 1,078 lake sturgeon locations were collected for habitat and movement analysis. Data from an additional 710 lake sturgeon locations were collected during greater than 100 commercial barge passage events. Preliminary analysis indicates that, despite the system of navigation dams in place on the Upper Mississippi River, lake sturgeon are highly mobile. One sturgeon moved 170 km through five navigation dams. Fifty-four occurrences of passage through navigation dams were observed and 46% of tagged sturgeon moved through at least one dam. Dams may obstruct lake sturgeon movement in tributaries of the Upper Mississippi River. Nearly half of the lake sturgeon tagged in Pool 10 moved 140 km up the Wisconsin River, a major tributary of the pool, where a hydroelectric dam prevented further migration. The lower Wisconsin River was an important habitat for lake sturgeon tagged in Pool 10, accounting for 21- 48% of sturgeon location, seasonally. Other habitats frequently used by lake sturgeon tagged in Pool 10 included main channel, channel border, and secondary channel, which seasonally accounted for 50-67% of sturgeon locations. Tailwaters were rarely used by this group. For lake sturgeon tagged in Pool 5a, use of the impounded area in which they were tagged remained above 39% during spring through fall. Similar to Pool 10 sturgeon, 31-47% of locations for Pool 5a tagged sturgeon were in main channel, channel border, and secondary channel habitats. However, tailwater habitats were used more frequently by sturgeon tagged in Pool 5a; accounting for 5-7% of sturgeon locations. The observed high use of main channel and channel border habitats indicates the high potential for encounters between lake sturgeon and commercial barge traffic. Some tagged lake sturgeon appeared to be forced out of channel habitats as barges approached the fish location. Others showed no reaction, exposing the fish to risk of propeller entrainment. Further analysis will focus on habitat selection by tagged lake sturgeon, hydraulic conditions at navigation dams during lake sturgeon passage, and lake sturgeon behavior during commercial barge passage.
Source http://www.mississippi-river.com/umrcc/newsletters/1999-01/newsletter.html
