Protecting Aquatic Life During Construction

Release Date: Aug 9, 2022

Contact(s): Joseph Black

LA GRANDE, Ore. (August 8, 2022) – Guided by  scientific research, on the ground experience, nets, and a desire to protect aquatic life, employees with the Wallowa-Whitman National Forest (WWNF) and biological field technicians with the Grande Ronde Model Watershed (GRMW) recently conducted a fish salvage project in a portion of Limber Jim Creek.

Relocating the fish outside of the construction area is an important part of the Limber Jim Creek project, said WWNF Fish Biologist Sarah Brandy.

“When the U.S. Forest Service has project work that occurs in stream channels, we are required to work within a certain timeframe that will have the least amount of impact on fish and aquatic life,” said Brandy, who led the project. “We also follow permits that require isolating a construction area, removing fish from this area and moving them to a safe place upstream until the work is complete.”

Removing fish from the stream includes setting up and securing two block nets, one upstream and one downstream – then relocating the fish in-between. These nets are held up using trees along the sides of the stream and large rocks that secure the net to the streambed.

The salvage crew then walks up and down the stream, with an electrofishing device and nets, surveying for any remaining fish in the now blocked off section of stream.

This process known as electrofishing, uses an electrical current to temporarily stun fish making them easier to catch. Electrofishing relies on two electrodes which deliver and electric current from the anode to the cathode through the water. The cathode or “tail” is a three-meter braided steel cable that trails behind the operator.

“A fisheries biologist with appropriate training in both human and aquatic safety, runs the backpack electrofisher, ensuring that the voltage is on the lowest effective settings so that fish and aquatic life are not harmed or damaged,” said Brandy.

The other technicians then capture the fish in nets and relocate them to a place in the stream upstream of the work isolation zone.

 

“By placing the fish upstream, they are able to migrate freely while remaining safe from the dangers of a construction site,” explained Brandy.

The construction project, funded by the Confederated Tribes of the Umatilla Indian Reservation, Bonneville Power Administration and the U.S. Forest Service, is replacing an existing culvert on a forest road. The culvert was undersized and not aligned correctly to the stream, causing the stream to erode the road on the upstream side of the culvert and cause conditions that were not passable to fish and aquatic life at certain flows. The new concrete bridge spans the whole creek and is wide enough for the creek to flow unimpeded at high flows.

“Correcting obstructed fish passages is a high priority for conserving and restoring fish populations,” said Brandy. “It helps connect fish habitat and gives fish and other aquatic life access to upstream areas.”

The culvert replacement also benefits the local community by protecting native fish resources, correctingproblem road sections, and utilizing local contractors to boost local economy.

The U.S. Forest Service keeps sections of stream blocked for the shortest amount of time possible so that fish and aquatic organisms remain unharmed and can swim to upstream and downstream habitats as soon as possible after construction.

More information about the Wallowa-Whitman National Forest is available at https://www.fs.usda.gov/wallowa-whitman.