Images

A free-drifting sturgeon embryo was captured in the Lower Missouri River in late August.  Most sturgeon in the lower Missouri River spawn in the springtime. 

Scientists release a tagged pallid sturgeon from a tracking boat on the Yellowstone River in Montana. 

USGS Fishery Biologist, Pat Braaten, and biologists from USGS Columbia Environmental Research Center and the Fort Peck Field Office release a telemetry-tagged, female pallid sturgeon after recapturing her to check her reproductive status.   She was still full of ripe, black eggs, and had not yet spawned when she was netted.

Biologist, Dave Combs prepares a tracking boat (foreground) and a DIDSON survey boat (background) to search the Yellowstone River for tagged pallid sturgeon, Near Fairview, Montana.  Pallid sturgeon in Montana are tagged with radio telemetry transmitters that are detected with large antennas mounted the boats.

Biologists prepare to perform ultrasound and an egg biopsy on female pallid sturgeon, radio code 30, to determine how close to spawning she is or whether spawning may already have occurred.  Biologists from Montana Fish, Wildlife and Parks determined that code 30 eventually spawned in the Yellowstone River on July 19-20, 2012.

A large male pallid sturgeon captured by the USGS on the Yellowstone River is scanned with a portable ultrasound device to determine if it is “ripe” and ready to reproduce.

USGS biologists drift trammel nets on the Yellowstone River, near Fairview, Montana to capture male pallid sturgeon.

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.

Female pallid sturgeon, PLS11-007, is released back into the Missouri River after an ultrasound evaluation

The Columbia Environmental Research Center's R/V Slim Funk is shown. 

These silver and bighead carp were collected on the Illinois River to learn more about the anatomy and physiology of Asian carp. This information will guide the development of potential biological or chemical controls as part of an integrated pest management approach for natural resource managers.

The sharp scutes along the back of the pallid sturgeon can be seen above the murky water it lives in. 

Following surgery and transmitter implantation, pallid sturgeon PLS11-002 was released at her capture location in the Lower Missouri River.

An incision just big enough to fit the transmitter is made in the belly of the sturgeon and a few stitches close it up.  The stitches eventually dissolve but a small scar remains visible.

Following surgery and transmitter implantation, pallid sturgeon PLS11-002 was released at her capture location in the Lower Missouri River.

USGS scientist records data from the flowmeter measuring the volume of water sampled by the ichthyoplankton sampling net.

USGS scientist retrieves the sampling net from the Missouri River.

Silver carp are a large a troublesome invasive species from Asia found in the great rivers of the central United States. Silver carp have been observed to jump in response to rocks thrown in the water, passing trains, geese taking off from the water, or just when they unexpectedly find themselves in a tight place.

Standing on the Earth and Dam at Cougar as the fog rolled in and over the tailrace. (South Fork of the McKenzie River)

After gastric tagging the adult Chinook, it was released back into the Klickitat River.

Standing on the Earth and Dam at Cougar as the fog rolled in and over the tailrace.