Over the past couple of weeks, biologists from the USGS and Montana Fish, Wildlife and Parks have been tracking pallid sturgeon in the Yellowstone River while USGS hydrologists map their habitats. This pallid sturgeon population has access to the Missouri River between Fort Peck Dam and Garrison (Sakakawea) Reservoir, and to the Yellowstone River from its confluence with the Missouri River upstream to the Intake Diversion Dam in Montana (see previous post titled “Rising Water” for a map of this area). At present, there is no evidence of successful recruitment in this population of about 125 wild adult pallid sturgeon although previous studies have shown that reproduction occurs.
Quite a bit different than the Lower Missouri River, the Yellowstone River is partially braided, with many gravel bars and islands. Like the Missouri River this year, the Yellowstone River is experiencing a large amount of water due to increased snowpack since October 1, 2010 and heavy rainfall in spring 2011. This inundation has caused the river to expand onto low-lying floodplains adjacent to the channel.
Recent work on the Yellowstone River has focused on tracking wild male and female pallid sturgeon and assessing their migration pathways. Using an acoustic Doppler current profiler (ADCP), hydrologists measure depth and water velocity of a river transect at known sturgeon locations. Comparing the water velocity at the known location to velocities of other nearby locations in the channel transect, we hope to understand hydraulic attributes (depth, velocity) used by pallid sturgeon during upstream migrations. This information can be used to inform engineers designing fish passage structures such as the Intake Diversion Dam in Montana.
This work will continue until water temperatures in the Yellowstone rise and spawning occurs. At that point, our focus will shift to validating spawning success and characterizing the spawning sites.
Contributions by Brandon McElroy & Pat Braaten