Images

Figure 3. Pallid sturgeon free embryo at approximately 5 days post-hatch, approximately 14-15 mm (about 0.57 of an inch) in length.

Pallid sturgeon free embryo at approximately 10 days post-hatch, approximately 19-20 mm (about 0.77 of an inch) in length.

Pallid sturgeon free embryos on the day of hatch, approximately 8-9 mm (about 0.33 of an inch) in length.

A 31-mm sturgeon captured in the Missouri River near Williston, North Dakota, on July 8 using a beam trawl. Sampling efforts occurred in support of a recent inter-agency collaborative drift experiment involving 700,000 sturgeon embryos. This sturgeon will be genetically test to see if it is from those used for the experiment.

USGS fish biologist Dr. Pat Braaten and student contractor Garrett Cook inspect contents of a net during night sampling on the Upper Missouri River.

USGS Fish Biologist Dave Combs searches through net contents for larval fish during night sampling on the Upper Missouri River.

Research hydrologist Dr. Susannah Erwin retrieves fluorometer from the Upper Missouri River to download dye trace data.

USGS fish biologist Dr. Pat Braaten and student contractor Garrett Cook inspect contents of a larval fish net during night sampling on the Upper Missouri River.

A U.S. Geological Survey hydraulic habitat assessment boat in not enough water.

USGS fish biologists launch at sunset on the Upper Missouri River for a night of sampling for larval pallid sturgeon.

Typical contents of a net deployment showing larval fish, possibly pallid sturgeon.

A US Geological Survey hydroacoustic survey boat measures velocity profiles on the Upper Missouri River.

Research hydrologist Dr. Susannah Erwin and hydrologic technician Brian Anderson inspect ADCP data on the Upper Missouri River.

Simultaneous mass release of 700,000 free embryos from boats distributed across the channel of the Upper Missouri River.

Distribution of free embryos to boats in preparation for mass release.

Pre-deployment briefing for the Upper Missouri River Pallid Sturgeon Drift Study. Fish biologists and physical scientists from Montana Fish Wildlife and Parks, US Geological Survey, U.S. Fish and Wildlife Service, University of Montana, Nebraska Game and Parks Commission, and US Army Corps of Engineers go over the sample design and assignments.

Student Contractor Garrett Cook processes a drift sample collected on June 27 shortly after the free embryos and beads were released. Note the small cluster of pallid sturgeon free embryos and green beads in the lower portion of the sorting tray. These embryos and beads were elements of the Upper Missouri River drift experiment.

USGS scientists prepare to mix rhodamine-WT dye for the dye trace experiment.  The suits are to keep the harmless dye off of clothing.

The rhodamine-WT dye was injected in the river uniformly across the channel.

USGS scientists conducted a dye-tracer study in June 2016 on the Missouri River about 10 miles downstream of Fort Peck Dam, Montana. The public can expect to see the Yellowstone River turn a similar color in the vicinity of the injection site when scientists conduct a dye study near Glendive, Montana in late June, 2017.

Macro photo of a developing pallid sturgeon embryo. Developing embryo appears light gray