Habitat surveys of 2015 pallid sturgeon spawning patches on the Yellowstone River

Science Center Objects

USGS research vessel

Figure 1. USGS research vessel outfitted with a compact multibeam sonar echosounder system with an inertial motion unit and real time kinematic positioning global positioning system (RTK GPS) surveys the Yellowstone River near Fairview, North Dakota.

(Public domain.)

During the last two weeks of June, USGS habitat crews surveyed the pallid sturgeon spawning reach of the Lower Yellowstone River near Fairview, North Dakota.  Using a compact multibeam sonar echosounder system with an inertial motion unit and real time kinematic positioning global positioning system (RTK GPS) mounted on a jet boat (figure 1), crews conducted high-resolution surveys and mapped features of the river bed in pallid sturgeon spawning patches (figure 2).  Multibeam sonar has been used in recent years to understand pallid sturgeon spawning habitats on the Lower Missouri but these efforts were the first to do so on the much shallower Yellowstone River.

Multibeam sonar depth map showing sand dunes and locations of reproductive female code 41 and multiple male pallid sturgeons

Figure 2. Multibeam sonar depth map showing sand dunes and locations of reproductive female code 41 and multiple male pallid sturgeons from June 13 to June 15, 2015 during a presumed spawning event near Fairview, North Dakota.

(Public domain.)

Multibeam sonar maps the river bottom in great detail with a “sweep” or ping of soundings taken at up to 40 times per second. This generates a very dense cloud of points which allows scientists to generate high-resolution maps of the bottom of the river and visualize features such as sand dunes, submerged trees, and scour holes (figure 3). By conducting multiple passes with the sonar throughout the day,  sand dune movement can be mapped to calculate the rate of sand dune migration.  This information can be used to advance understanding of how spawning habitat may change while eggs are incubating in the substrate.

Image showing raw multibeam point cloud in the pallid sturgeon spawning habitat patch near river mile 5.9 on the Yellowstone

Figure 3. Image showing raw multibeam point cloud in the pallid sturgeon spawning habitat patch near river mile 5.9 on the Yellowstone River. The image is approximately 20 meters wide, is looking downstream on a sand bar, and shows sand dunes that are approximately half a meter high from crest to trough.

(Public domain.)