On the Right Path

“We have a boy, code 52, on his way to Intake Dam.  We’ve tracked him all day through bends and side channels.  He is a couple of miles away from the Dam.  Can you spare a crew to track him till dark?”

This was the phone message given from USGS Biologist, Pat Braaten to USGS crews as they were finishing a long day chasing large, fast moving pallid sturgeon up and down the Yellowstone River in Montana on Saturday, June 9The crews were working to assist the USGS Fort Peck Field Office and the Montana Fish Wildlife and Parks (MFWP) to document spawning locations and behavior in the lower Yellowstone River (see Headed North).

The crew responed, “On our way.”

In addition to documenting spawning migration behavior and finding spawning locations, the work on the Yellowstone River by USGS and MFWP is focused on trying to determine how pallid sturgeon use the river as they migrate (see Path of Least Resistance).  Most importantly, biologists were keenly interested in how easily pallid sturgeon migrate through the last few miles of river downstream from Intake Diversion Dam (about 73 miles upstream).  Managers and Engineers from the U.S. Army Corps of Engineers, Bureau of Reclamation, U.S. Fish and Wildlife Service, and MFWP are working to design a way for pallid sturgeon to pass over or around the dam, and continue their migration upstream (see Intake Diversion Dam Modification Project).  The pathway that the sturgeon choose, and the ease with which they can negotiate through the turbulent waters and jumble of rocks downstream of the dam could prove critical to the success of that project, and the long-term viability of this population.

The USGS tracking boat made it up to Intake Diversion Dam and located male pallid sturgeon, code 52, less than two miles downstream from the Dam.  He was still moving.  The tracking team listened to the telemetry receiver and followed as he swam steadily upstream along the right descending bank, reaching the Dam just as the sun began to set.  The tracking crew pulled their boat from the water in the dark, guided back to the boat ramp by the small fires set by campers and paddlefish fishermen.  Within hours the precise locations collected by the tracking boat were transferred to the habitat mapping crew, and the plan to map the depths and velocities of code 52’s pathway the next day, were completed before the hotel lights dimmed for the night.  Surprisingly, USGS tracking crews located code 52 again a few days later, almost 70 miles downstream near the confluence with the Missouri River.

 

Precise telemetry locations documenting the migration pathway of male pallid sturgeon, code 52, as it approached Intake Diversion Dam, Montana on June 9, 2012.

The sun sets below the horizon as USGS telemetry-tracking crews follow the upstream migration of male pallid sturgeon, code 52, below Intake Diversion Dam, Montana on June 9, 2012.

By Aaron DeLonay

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