The Utah Department of Natural Resources stocked thousands of young rainbow trout in Deer Creek Reservoir this week.
Stocking fish is a practice in which they are raised in controlled environments at different hatcheries. Then, when the fish are the right size, they are transported to local reservoirs, lakes and rivers.
The rainbow trout brought to Deer Creek Reservoir this week were about 10 inches long and half a pound each. They were raised at the Springville Hatchery.
Utah Division of Wildlife Resources Conservation Outreach Manager Mike Packer said trout thrive in colder water, so introducing the fish in the fall gives them the best chances of growth and survival. The Division of Wildlife Resources operates under the Department of Natural Resources and focuses on managing, sustaining and enhancing the state’s wildlife population, conserving habitats and regulating hunting and fishing.
Rainbow trout are a nonnative species, but they’re still vital to the aquatic ecosystems. They’re also popular fish for anglers and have become a staple in the state’s waters. Utah’s only native trout species is the beloved state fish, the cutthroat trout.
Packer said trout are popular in Utah because they’re a great catch for all kinds of anglers.
“(Trout) have become the desired species. … That has propelled making trout a priority,” Packer said. “Utah is one of our western states that is feeling the effects of a changing ecosystem (and) changing waters.”
Part of that shift, Packer said, will require monitoring rainbow trout entering the waters this fall to see how they grow over the next few months.
Managing fisheries is a complex and detailed task, especially when it comes to balancing populations.
“Think of it as a unique community of fish,” Packer said.
Biologists can observe fish populations over time, see how they interact and learn which species anglers prefer to catch.
Because rainbow and cutthroat trout are so similar, state biologists must be extremely mindful of keeping the rainbow trout population balanced.
One particular risk of introducing rainbow trout to a population with native cutthroat trout is possible crossbreeding between the two species. Because the cutthroat trout is native, Packer said, the goal is to protect the species as it is.
“Even though rainbow is not a native species to Utah, we can be strategic in how we introduce them or put them into systems with species like cutthroat in certain areas,” Packer said.
Springville Hatchery Assistant Supervisor Brennan Hannifin and Department of Wildlife Resources Conservation Outreach Manager Mike Packer worked with biologists to plan how many fish would be brought to the reservoir. Credit: Jonathan Herrera/Park Record
Officials control crossbreeding by sterilizing rainbow trout when they’re in hatcheries.
Springville Hatchery Assistant Supervisor Brennan Hannifin said the fish eggs are treated with warm water for a few minutes to create “triploid” fish, causing sterility.
“If we were going to put a rainbow trout in a place with cutthroat or … it feeds somewhere where there’s going to be other fish, (and) we don’t want them crossbreeding with or taking over a population, that helps it because … you can manage it,” Hannifin said.
In addition to Deer Creek Reservoir, Strawberry Reservoir and Little Dell Reservoir are also stocked with sterile rainbow trout.
Depending on where the fish are going, different transportation methods move them from hatchery to water.
In more remote areas, biologists carry fish in backpacks or while hiking or riding on horseback to access rivers and ponds. Sometimes, the state drops fish from airplanes or helicopters.
At Deer Creek Reservoir, fish are on a truck that’s backed up onto the boat ramp. The truck had a large tank on the back to hold the fish during travel.
Springville Hatchery Assistant Supervisor Brennan Hannifin stands at the back of the “single tanker” truck to transport trout from the hatchery to the reservoir. Credit: Jonathan Herrera/Park Record
Hannifin said the tank had a cooler and oxygen circulation system to keep the fish stable. The tank has a plug on the back that, when opened, lets the fish drain out into the reservoir.
Because other species that prey on trout are less active in colder months, the trout introduced this week will have the best chance of growing to a full size, between 16 and 19 inches long, by spring.
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