Idaho Power Company biologists have begun a three-year survey of white sturgeon in the Snake River below Hells Canyon Dam and a portion of the lower Salmon River.
The three-year study is the first in a decade and is being conducted in cooperation with state, federal and tribal entities. IPC owns and operates three dams long the Idaho-Oregon border that make up what is called the Hells Canyon Complex. Hells Canyon is the lowermost of those three hydro projects. The complex blocks up and downstream passage of salmon, sturgeon and other fish species.
From now through November, the company biologists will use setlines to catch the giant, prehistoric-looking fish that have changed little over the past 175 million years. Sturgeon are the largest freshwater fish in North America and can weigh as much as 1,500 pounds and reach lengths of more than 12 feet, according to the company.
The sturgeon will be weighed, measured, scanned for the presence of an electronic tag, cataloged and released.
The purpose of the study is to update population data for white sturgeon in this reach, and implement a standardized monitoring program that tracks sturgeon abundance by assessing the population every 10 years. The information gathered will be important for monitoring the long-term success of white sturgeon in Hells Canyon.
“This is the largest monitoring effort for sturgeon that Idaho Power performs,” said Ken Lepla, Idaho Power senior biologist. “We are targeting this population because it is one of only two productive, self-sustaining sturgeon populations remaining in the Snake River upstream of Lower Granite Dam.” The other population is above the complex on the Snake reach between the IPC’s Bliss and the C.J. Strike dams in south central Idaho.
While both populations are self-sustaining, neither is big enough for catch-and-keep fisheries. Fishing is allowed, but any big fish caught must be released.
Crews are using baited setlines, gear that is commonly used in white sturgeon studies throughout the Columbia River basin. The setlines are rigged with “circle” hooks that prevent sturgeon from swallowing the hook because of its unique shape. This gear has been used in Idaho Power’s white sturgeon surveys over the last 20 years without incident to sturgeon, and the field crews strive to maintain this record.
Each setline is marked by an orange buoy and metal tag identifying the study and Idaho Power’s contact information. All setlines are checked daily and at frequent intervals. The public is asked to avoid contact with the setline gear; tampering or vandalizing the gear may cause unnecessary harm to fish if the setlines cannot be recovered.
The survey is part of Idaho Power’s White Sturgeon Conservation Plan, which provides for periodic monitoring of sturgeon populations associated with the company’s hydroelectric projects. The plan can be found at:
“The middle reaches of the Snake River between Hells Canyon and Swan Falls dams, as well as reaches upstream of Bliss Dam to Shoshone Falls (a natural barrier), contain only small populations and show little or no detectable recruitment,” according to the plan. “Factors that have played a role in sturgeon decline in other river systems -- altered habitat, pollution, historical exploitation, and fragmentation -- have also contributed to the current status of sturgeon in the Snake River.”
The long-term goal, as defined in the WSCP, is to mitigate for IPC project-related impacts in order to provide for healthy populations of white sturgeon in each reach of the Snake River between the mouth of the Salmon River and Shoshone Falls, not including the reach between Upper Salmon Falls and Lower Salmon Falls dams.
“… short-term objectives are to maintain and/or enhance population viability and persistence of white sturgeon below Bliss and Hells Canyon dams and, where feasible, begin to reestablish recruitment to populations where natural recruitment is severely limited,” the plan says.
The survey – basically from below Hells Canyon Dam down to the head of Lower Granite Dam’s reservoir -- is conducted in coordination with state, tribal and federal entities including the Idaho Department of Fish and Game, Oregon Department of Fish and Wildlife, Washington Department of Fish and Wildlife, Nez Perce Tribe, U.S. Forest Service, and Bureau of Land Management. Lower Granite is in southeast Washington.
The company’s plan includes sharing information with fish management agencies and cooperatively identifying measures to improve or maintain populations of this great fish.
For more information about the project, including a map of the area being surveyed, visit www.idahopower.com/ourenvironment and click on the sturgeon.
Idaho Power serves nearly 500,000 customers throughout a 24,000-square-mile area in southern Idaho and eastern Oregon.