For Immediate Release May 7, 2002

Spring Chinook to be Stocked in Diamond Lake

ROSEBURG - History will be in the making on May 17 when the Oregon Department of Fish and Wildlife stocks hatchery spring chinook in Diamond Lake. These 24,000 legal-sized fish are part of an experimental stocking program designed to provide a fishery for the lake that has been overrun with tui chub.
"In the ocean, spring chinook aggressively pursue small fish like herring and sardines, so we hope they will swim after tui chub in the same way," says ODFW district fish biologist Dave Loomis. "We chose to stock the springers for this predatory behavior and hope they think the lake is a small ocean with lots of small fish to eat."
According to Loomis, one of the goals of the experimental stocking program is to find a fish that will actively prey on chub so the return rate to the angler is higher than the past few years with rainbow trout stocking. "We know the lake has plenty of chub, and these salmon can't eat every last one to solve the problem long-term, but it's important to explore other opportunities for Diamond Lake anglers right now."
Diamond Lake has been a premier rainbow trout fishery since ODFW began stocking in 1910. No other trout species has been stocked in the lake's history. Tui chub were introduced in the early 1940s when anglers used them as live bait to catch large rainbow. The chub were eradicated by the fish toxicant rotenone in 1954 as the trout fishery collapsed from the impacts of these fish. As a result of the devastation at Diamond Lake, the former Oregon Game Commission made it illegal to use live fish for bait in the state of Oregon. However, chub were used illegally as live bait in the 1990s and have exploded to a population in the millions. The trout fishery has since declined, and along with it, the water quality of the lake.
Loomis and other biologists will be studying the spring chinook to determine how efficient they are at feeding on tui chub. "We really don't know how these landlocked chinook are going to fare in the lake, what their growth and overall survival rates will be," Loomis said, "and we need to know what we'll get in terms of a fishery." Diet studies will begin later this summer, continue into fall, then resume again the following two summers.
The spring chinook have been raised at Rock Creek Hatchery since October 2000 and will be released into Diamond Lake as 18-month-old smolts at a cost of $1.25 per fish. The salmon are eight to 10 inches and weigh about a pound each. Landlocked salmon are considered trout, so the bag limit is five fish per day, one of which can be over 20 inches.
Some of the fish will mature this fall and try to spawn in the lake, while most will mature the following two years. Ocean-going spring chinook average 15 to 20 pounds when they return to Oregon's rivers. Loomis predicts these landlocked salmon could grow to over 20 inches and weigh five to 10 pounds at maturity in a few years. The quality of the meat may also differ since the Diamond Lake chinook will have a much different diet than the ocean-going salmon.
Although ODFW biologists will intensively study the fishery, Loomis encourages anglers to catch and keep the spring chinook. "We're really interested to hear from the anglers what they think about catching and enjoying a feast on a lake-reared chinook," he said.
ODFW plans to stock Diamond Lake with 60,000 spring chinook next summer and will seek funding for another 60,000 in the summer 2004. Other stocking plans for this summer and fall include 20,000 trophy-sized rainbow trout, 26,000 legal-sized rainbows, and 50,000 fingerling rainbows.