MANTUA -- A worker dips a large net into the water, and as he begins to pull it out, its occupants wriggle and writhe, splashing water on everyone within a 10-foot radius.
The net is placed into a tub of frigid water on the back of a vehicle. After a minute or so, the commotion dies down, and Chris Haramoto reaches in and pulls out a rainbow trout weighing about 4 pounds.
"You'll know it when you hook this guy," Haramoto says.
The fish he was holding is one of 130 removed from the state-owned fish hatchery in Mantua and released into Hyrum Reservoir on Thursday in preparation for a fishing contest that begins next weekend.
Before taking them to the reservoir in a specialized truck equipped with two 2,000-gallon tanks, employees with the Utah Division of Wildlife Resources implanted each trout with an orange tag to distinguish the fish from the many thousands of other fish that call the reservoir home.
Beginning April 20, anyone with a valid Utah fishing license who catches one of the tagged trout can take it to the Hyrum State Park office and redeem it for one of a variety of prizes donated by Cache Valley businesses.
The contest will run until Aug. 31, or until all of the tagged fish are caught.
Haramoto, manager of Hyrum State Park, said the contest made its debut last year, when 300 hatchery trout were tagged and released into their new home.
"It's just a good way to get people out fishing," he said.
Of the 300 released last year, Haramoto said, less than half were caught. With so many other fish already in the reservoir, the odds of catching a tagged trout aren't great but still good enough to draw many anglers who otherwise might not bother, he said.
The fish that were tagged and stocked Thursday had been raised in the hatchery for three years and weigh about 3 pounds on average -- a pretty good size for a rainbow.
Anglers hoping to hook into one of the contest fish might do well to start trying as soon as the contest begins, said Quent Bradwisch, a fisheries biologist with the DWR.
"They have been off their feed for two days, so they should be ready to eat when they hit the water up there," Bradwisch said.
A wide range of prizes awaits the successful anglers -- everything from a guided fly-fishing trip to gift certificates for local restaurants.
"There's something for everyone," Haramoto said.
Chris Penne, another DWR biologist, said the contest fish are "brood stock" -- fish bred from eggs and milt gathered by DWR employees. He said the agency has decades of experience transporting fish around the state without harming them.
"You just have to make sure the water stays moving in the tank," Penne said.
Before they are tagged and moved, the fish are placed in a water tank that has been treated with an anesthetic that calms them down so they can be handled more easily.
Penne said rainbows were the fish of choice for the contest because they are known for their fight, which makes them a fun fish to catch.
For the best chance of success, he recommends PowerBait or spinners for shore anglers. Boaters might be best served by trolling, a technique in which anglers let their lure out on a line and simply pull it along behind the boat as they move around the water.
The Mantua hatchery does a lot more than just supply Hyrum Reservoir, Bradwisch said. It provides rainbow and Bear Lake cutthroat trout eggs to 10 other hatcheries statewide. At those hatcheries, the fish are bred and raised to a size of about 10 inches before being transported and stocked in lakes and reservoirs around the state.
The hatchery provides between 5 million and 10 million eggs every year, Bradwisch said.
"Fish that started as eggs here could be found just about anywhere in the state," he said. "As far as distribution, we try to keep them local, but sometimes we have to make longer drives."
In general, the less time the fish spend on the road, the better off they are when they reach their destination, he said.
Haramoto said holding the contest in Hyrum Reservoir again was a no-brainer after seeing a high level of interest and participation from the community last year.
"It was so successful last year that it was an easy decision to do it again this year. We encourage everyone to come out and give it a try."