After treatment, the lake was re-stocked with rainbow and Lahontan trout in addition to warmwater species. Angler days skyrocketed from 1,500 in 1983 to 35,000 in 1988 when the trout fishery peaked.

The newly stocked trout sparked the initial surge in angling interest, at least until the warmwater fish grew to catchable size. The fish population transitioned over the next 15 years until walleyes became the dominant species.

Walleye World
The predaceous walleyes then did what walleyes do: They gobbled up all the other game fish except for the few that could escape into the weeds where the walleyes couldn't go. Paradoxically, as the walleye population rose, angler success dropped, while angler complaints about lack of catchable fish increased.

WDFW creel surveys verified the low catch rate of less .25 fish per angling hour. Yet, 2001-05 fish samplings revealed a "dense walleye population with a large proportion of harvestable sized fish."

Despite the walleye numbers, the anglers stayed away, opting instead for Moses or Banks lakes. Local businesses dependent on angling-related tourism suffered.

WDFW knew a change in the management plan was necessary to jumpstart the recreational fishery, so it developed five potential options for enhancing the fishery. For two years, they tried the low-budget option of increasing the walleye bag limit and lowering the minimum size. There was no notable success in the catch rate or angler days.

A loose-knit organization known as Sprague Lake Users Group and George Potter, projects chairman of the Inland Empire Fly Fishing Club, joined to give their opinion on the lake. They overcame initial skepticism from WDFW, which figured the walleye clubs would oppose any rehab plan. But after a series of public meetings, the state learned that walleye clubs and bass anglers supported rehabilitation. Soon it was full speed ahead with management Option 5, the rotenone solution.

The Rotenone Solution
Rotenone, a naturally occurring substance from the roots of tropical plants, is the treatment chemical of choice because it kills aquatic species and quickly breaks down to an inert substance.

But it was no small task to effectively treat a six-mile-long lake. The WDFW used 4,000 tons of rotenone powder and 900 gallons of liquid to treat Sprague, Hallin, Finnell and Cow lakes, as well as the creeks and backwaters connecting those bodies of water. Some of those backwaters were marsh, not otherwise accessible by foot or boat, so the WDFW used a helicopter to treat those areas in an effort to slow the infiltration of carp of other unwanted species.

The Inland Empire Fly Fishing Club donated $2,000 to help pay for the rehabilitation project. They were joined by the Spokane Fly Fishers. Dan Ferguson, past-president of the Spokane Fly Fishers, said his club tossed in $1,000 to help pay for the helicopter. In a true grassroots process that spanned the trout-fishermen warmwater divide, these two fly clubs were joined by Walleyes Unlimited and Inland Northwest Wildlife Council plus some 30 to 40 volunteers with a common goal: return Sprague Lake to its former fishing glory.

After the rotenone was applied, WDFW let the lake settle until May 2008 when an interesting restocking program began. Heavily stocked with 160,000 catchable-sized rainbows and 250,000 rainbow fry, WDFW added 80,000 Lahontan cutthroat fry, as well as bluegills, black crappie, largemouth bass and channel catfish. The WDFW also restocked some 4,000 black crappie and 60 channel catfish it removed from the lake before applying rotenone.

FAT TROUT
Put aside any notions of fishing Sprague and only catching a bunch of skinny pan-sized trout. Rainbow fry planted in spring 2008 at 3 to 4 inches measured a whopping 16 inches in October 2008. By the time you read this, those silver-bright rainbows will have added additional inches and pounds. Just be thankful your children don't grow 400 percent over one summer like these fish!

The rainbows being taken home for the table sport a distinctive reddish-pink flesh, much the color of chinook salmon.

Chris Donley, WDFW district fish biologist, said the color comes from carotenoids. The same natural fat-soluble stuff that makes carrots orange and tomatoes red are contained in any number of zooplanktons and aquatic insects the trout eat.