Fish and Wildlife staff told Chelan County PUD commissioners last week that an effort to save water at PUD hatcheries also seems to be producing juvenile salmon and steelhead that appear stronger and travel faster to the ocean once they are ready.
Instead of building long, rectangular or oval tanks out of concrete, hatchery managers have turned to circular tanks of fiberglass, with a constant recirculating water flow. The circular current helps dispose of waste more efficiently at a central drain, and the system requires only about one-eighth the water of a standard hatchery raceway.
With fish swimming against the circular current, the system seems to be producing fish that are stronger and make it downstream to McNary Dam on the Columbia in 16 days instead of the usual 22 days.
Shorter travel time to the ocean means less chance that small fish will run into predators along the way – and therefore have better survival all the way to the ocean.
While cautioning that results only cover one year of testing so far, staff said the preliminary findings are creating a lot of interest in fishery management circles.
The PUD is required to produce hatchery fish as part of its “no-net-impact” requirement in Habitat Conservation Plans for Rocky Reach and Rock Island dams. The PUD is trying to develop new facilities so it can move away from using the antiquated Eastbank Hatchery facilities on Turtle Rock Island just north of Rocky Reach Dam in the Columbia River.
The new circular water reuse system is in place for steelhead rearing at the PUD’s Chiwawa hatchery, and it is also being used for summer Chinook at Eastbank.
“We can raise a high-quality fish,” said Joe Miller, PUD hatchery program manager. He said further studies would continue tracking the system to see if the early successes continue.