State prepares to rehab Sprague Lake
Sprague Lake, which extends across the Adams-Lincoln county line just south of Interstate 90, is being prepared for Washington’s largest fisheries rehabilitation project.
Sport fishing will close Monday until further notice.
State Fish and Wildlife Department workers plan to start applying rotenone to the 1,860-acre lake and 310 acres of associated waters, including Cow Lake, on Oct. 8 or 9 to kill the current carp-infested fishery.
For liability reasons, the public will not be allowed to salvage fish killed by the rotenone treatment.
“There will be a lot of dead fish coming up, mostly carp,” said Chris Donley, department district biologist. “But what you’ll see is not a good indication of what’s in the lake, since a lot of the dead fish sink.”
The plan calls for restocking the lake next spring with black crappie, bluegill, largemouth bass, channel catfish, rainbow trout and possibly sterile tiger muskies.
The main difference between this project and the 1985 Sprague Lake rehabilitation is that no walleye or smallmouth bass will be restocked.
“With fewer fish species, the fishery will be easier to manage and keep in balance,” Donley said.
Three years of research indicates the lake’s fishery currently is about 55 percent walleye, 30 percent carp and tench, 6.4 percent channel catfish and brown bullhead, 6.1 percent crappie and bluegill, 2.5 percent bass and 1 percent rainbow trout.
The Sprague rehabilitation will restore the balance of game fish in the lake, said John Whalen, department regional fisheries manager, noting that predatory walleyes have exceeded the prey base.
But the huge population of carp also is a major factor in the lake’s decline. The prolific bottom-feeding fish deteriorate water quality, which inhibits other fisheries and aquatic growth important to waterfowl.
Cost of the project is nearly $380,000, including staff time. Local economy benefits from a rejuvenated sport fishery is expected to be in the millions, state officials say.
Agency staffers recently devoted three days of electro-fishing on Sprague to stun and net about 4,000 black crappie 3- to 4-inches long. The fish will be kept at the state’s warmwater hatchery in Grant County for restocking in the lake next spring.
“We have sources for the fish we’ll be putting back into the lake, but crappie are the hardest fish to come by, so we wanted to get as many as we have room to keep at the hatchery for restocking,” said Mark Divens, department biologist. About half of those fish are likely to survive the capture, transport and over-wintering ordeal, he said.
The biologists incidentally captured 27 walleyes ranging 2-4 pounds and released them into Liberty Lake, Divens said.
About 75 channel catfish ranging from 7 to 20 pounds have been caught on trot lines and taken to the hatchery for release back into Sprague next spring.