As dawn cracks into the early morning sky, environmental manager Ashley Lopez and fisheries biologist David Colby join Bryte Yard technicians Aaron Siemsen and Greg Jerman near the boat dock of Elkhorn Boat Launching Facility along the lower Sacramento River in West Sacramento, California. At the dock, the river is calm as the team slips on their life jackets and steel-toed boots before loading their gear onto a 24-foot-snub-nosed aluminum district boat.
Siemsen and Jerman carefully lower the boat steadily into the still river, communicating with hand signals. Once aboard, the team prepares four large Juvenile Salmon Acoustic Telemetry System (JSATS) receivers and four smaller Innovasea VR2W 69-kilohertz (kHz) receivers for deployment. These receivers are essential tools to a telemetry survey - in which data is gathered to help scientists monitor migration patterns, survival rates, movements and behavioral changes in aquatic species, like salmon and green sturgeon.
The team will ride down the Sacramento River to deploy the two JSATS receivers and two VR2W receivers on each side of the river at two locations. The receivers will be placed deep into the river where they will be anchored to the bottom of the riverbed. Each receiver will have a cable mechanism tied to a steady trunk near the riverbank to hold the receivers in place.
“Acoustic telemetry is used to track movement of tagged fish using sound signals,” says Ashley Lopez. “Small transmitters, or tags, are implanted in the fish, and each tag emits a unique series of sound pulses. Stationary receivers are ‘listening devices’ that detect and record the sound pulses from the tags.”
At first glance, the JSATS receivers could easily be mistaken for a miniature model rocket. Cylindrical at their base, measuring six inches wide, 30 inches long and weighing around ten pounds each, they are much too large to be held with one hand, requiring a two-person lift. Despite their bulk, the receivers are built to withstand the elements, keeping a memory card safe inside while it stores the sound signals transmitted by tagged fish.
After riding out onto the river, Lopez helps identify the designated locations to place the receivers while Colby and Siemsen steadily attach the receivers to their mounts and Jerman ensures the team practices appropriate boat safety throughout the survey.
Telemetry surveys create usable, time-stamped data to inform habitat use and migration patterns along the river, such as migration presence or absence where fish may linger, and how their behavior changes with the seasons. The data gathered through these telemetry surveys is invaluable for researchers.
“The monitoring is vital in filling important data gaps on green sturgeon life history and micro and macro habitat utilization in the Sacramento River and the north Delta,” says Colby. “Data collected from USACE monitoring efforts may be used to model green sturgeon response to project repair features and mitigation required to compensate for any loss of available habitat.”
Since fish swim at depths beyond the human eye, fish are difficult to visually track when standing on a bank of a river. The transmitted signals captured during the survey allow for fish to be individually identified and for patterns to be quantified to help determine whether or not fish are being impacted by construction on nearby levees.
Collecting this data enables Sacramento District teams to balance environmental stewardship with its multi-million dollar flood risk management portfolio. This includes long-term efforts such as the Sacramento River Bank Protection Project, which supports critical erosion repairs, as well as projects like the American River Common Features Project and the West Sacramento Levee Improvement Project. Together, these projects rely on survey data to evaluate potential construction impacts across complex and environmentally sensitive areas.
The information collected is shared with the National Marine Fisheries Service (NMFS), a component of the National Oceanic and Atmospheric Administration (NOAA) responsible for administering the Endangered Species Act.
This coordination helps close data gaps and supports the assessment of potential impacts to federally protected species.
Through coordination with agencies like the National Marine Fisheries Service, survey results inform impact determinations and any necessary mitigation measures, providing the basis for construction to proceed while ensuring environmental considerations are fully addressed.
The district also collaborates with partners such as the California Department of Water Resources (DWR) and the University of California, Davis.
As a funding and implementing partner for levee and flood risk management projects, DWR uses the data to guide levee construction and comply with the California Environmental Quality Act (CEQA), allowing them to assess impacts from a state perspective. Similarly, UC Davis participates in the CEQA process and coordinates with state agencies to evaluate construction impacts and support informed decision-making.
After spending the day under the Sacramento sun, the team returns to the dock, packs up its gear, and heads home. Their work for the day is done. Docked JSATS and VR2W receivers will collect data for at least three months, providing USACE with valuable information to effectively balance environmental requirements with its flood risk management mission.
| Date Taken: |
11.03.2025 |
| Date Posted: |
12.30.2025 16:19 |
| Story ID: |
555410 |
| Location: |
WEST SACRAMENTO, CALIFORNIA, US |
| Web Views: |
24 |
| Downloads: |
0 |
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This work, Telemetry Surveys: Tracking Life Beneath the Surface, by Bertha Smith, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
