This is an archived article that was published on sltrib.com in 2011, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
There was a time not so long ago when Scofield Reservoir was considered one of Utah's premier trout fisheries. The boat ramps were crowded and the banks lined with families hoping to land a lunker trout.
The pressure has dropped in recent years as the fishing for large rainbows has dropped off and anglers are as likely to catch a Utah chub as they are a trout.
Fishing at Scofield has been adversely affected by the proliferation of nongame chubs over the past decade and an apparent fish kill in the winter of 2009. High water this spring has made it tough for anglers to access the reservoir in some spots.
Division of Wildlife (DWR) officials tried to combat the chub (which were likely introduced as illegal live bait) in 1995 by bringing in tiger trout — a hybrid mix between a brook and brown trout. The predacious trout appeared to be putting a dent in chub population — until 1997, when the chub went crazy.
"It was a textbook exponential growth curve," said fisheries biologist Justin Hart.
Biologists decided to add another effective predatory trout in 2009 by introducing Bear Lake cutthroat into Scofield. The idea was to try a similar chub management program as one that appears to be working at Strawberry Reservoir.
And while the tigers and cutts have been in Scofield for a while, they were not protected like they are at Strawberry. There, the implementation of a slot limit on tigers and cutthroat — all fish between 15 and 22 inches must be released — allows the fish to grow to a size where they are feeding on young chub heavily.
"We are a little behind on the Strawberry timeline of implementing the slot limit, but one of the great things about Scofield is that it is so productive that we see good growth on the trout and maybe that will help us make up the difference," Hart said.
Many anglers have been critical of the DWR for allowing anglers to keep double the state limit of trout at Scofield in 2007. They say it was increased take on the trout that allowed the chub to flourish.
Hart says that was not the case. The change was made to rekindle interest in Scofield for anglers who had departed for Strawberry, which was flourishing at the time. It didn't work.
"We did a creel survey in 2007 and we had less fish harvested and less hours fished at Scofield than when there was a four-fish limit," Hart said. "There was no over harvest."
Hart said after a few years of missing age classes, rainbows in the 15-inch range are starting to show up on fishing lines. He is hopeful that the trout populations, particularly the tigers and cutts, will grow in size and turn the tide of chubs. A graduate student from Utah State University is tracking the populations and should provide some solid data about the impact on the chub population.
But if it doesn't turn around, Hart says, there is another option: poisoning the reservoir and starting over.
"We have done some preliminary planning for a rotenone project," he said. "We hope things work out with our management plan, but we want to be ready to do something quickly if it doesn't."
A treatment at Scofield would run between $750,000 and $1 million and would shut down the fishery for a year, at least.
In the meantime, there may not be as many big rainbows as in the past, but tigers and cutthroats on the top end of the slot are being caught.
Tom Ogden of Price remains a frequent fly fisher at Scofield and he catches his share of chub, but he suggested fishing at more shallow depths to avoid the nongame fish. It is a particularly good method in the fall when the water cools.
Hart suggests that bait anglers use larger hooks to avoid the chubs.
"Imagine something a chub can't get its mouth around," he said.