The Nechako River's endangered white sturgeon could have a silt-free spawning site this spring if all goes according to plan.
The B.C. Ministry of Environment is seeking a company that can remove fine particles from a small section of the river where the endangered fish lay their eggs and rear their young.
It's part of a plan to help the sturgeon, a species whose evolution dates back to the dinosaurs, reproduce on their own.
For decades, the Nechako sturgeon have struggled to successfully spawn in the wild.
Scientists believe their slow disappearance from the river is linked to the construction of the Kenney Dam in the 1950s, which helps supply power to what is now the Rio Tinto Alcan aluminum smelters.
"The dam stopped the natural flow of the river," said Wayne Salewski, chair of the community working group for the Nechako White Sturgeon Recovery Initiative. "The water is never fast and fierce enough to flush all the silt downstream."
Instead, fine particles accumulate over the spawning beds, covering the coarse gravel needed by the sturgeon to hide and protect their eggs.
In 2011, substrate remediation involving the creation of two gravel spawning beds showed promise, leading to the survival of some baby fish. But over the next few years, the silt built up again. It was cleaned in 2016 with uncertain results.
The goal of this spring's work is to "repeat a similar test by removing the fines from the gravel/cobble material that was placed in 2011," says the government's Request for Proposals, which closes Jan. 27.
Tracking the condition of the cleaned substrate, as well as monitoring the project's success, will be a critical component this time around.
"Methods developed in the present study will be an integral part of substrate cleaning tests to be conducted in the future," says the RFP.
Salewski, who has been involved in sturgeon recovery efforts in Vanderhoof for more than 40 years, said the beds could be seeded with eggs and milt from the Nechako White Sturgeon Conservation Centre. The program typically releases one-year-old sturgeon into the river, but it's believed naturally-born fish would fare better.
"The hatchery fish simply aren't as wise," he said.
The efforts are just one part of an ongoing battle to save the sturgeon.
"There's never an easy blueprint to recovery. No one way is going to be successful. You really need to think of it as a multi-pronged attack."
