A better hatchery salmon and steelhead huh? Wasn't that what they promised with the broodstock programs? Of course the harvest addicts will greet this as the best thing since sodium sulfite. Maybe if they make the tanks oval WDFW could draw in a bunch of NASCAR fans!!!!
By Eric Mortenson, The Oregonian
Call it another example of survival of the fittest.
Researchers experimenting with juvenile salmon and steelhead at a Washington fish hatchery say fish raised in circular tanks with a swift current are faster and tougher than fish raised in the commonly-used rectangular raceways.
The findings come from a pilot project at Eastbank Hatchery in Wenatchee, Wash., carried out by Chelan County Public Utility District, the National Marine Fisheries Service and the Conservation Fund's Freshwater Institute. Researchers determined that fish raised in circular tanks migrated downstream faster upon release, reaching a checkpoint five days earlier than their brethren. More of them survived, as well -- 72 percent compared to 52 percent of fish raised in rectangular tanks, according to a Freshwater Institute news release. Also, the fish raised in circular tanks included fewer "mini-jacks," juvenile salmon that become sexually mature early and stay in freshwater rivers instead of migrating to the ocean. Researchers are concerned that hatchery-raised jack salmon can distort the genetic makeup of wild salmon over time.
Depending on the technology used, circular tanks can re-use up to 99 percent of the water in the system. The systems also collect waste and uneaten food, making them easier to keep clean, according to the Freshwater Institute. The institute, a non-profit based in West Virginia, advocates the sustainable use of water.
The findings are preliminary, but researchers are "extremely optimistic" that hatchery operations and water conservation efforts can complement each other, hatchery manager Joe Miller said in a news release. However, scrutiny is required because fish hatchery operations have a "history of unintended consequences" such as producing flawed fish, the news release said.
The research findings will be presented Dec. 7 at the Northwest Fish Culture conference in Portland.