Summit County’s Old Dillon Reservoir welcomes first California golden trout
A two-year, 1,000-mile journey finally came to an end this week for 2,000 of Summit County’s newest inhabitants.
On Tuesday the Old Dillon Reservoir Authority — consisting of Summit County and the towns of Dillon and Silverthorne — in conjunction with Colorado Parks and Wildlife and the U.S. Forest Service introduced the first population of California golden trout to Old Dillon Reservoir.
The introduction of the one- to two-inch fingerlings marks the latest step toward completing an expansion of Old Dillon Reservoir. The project, which is nearing its final phases, is about 15 years in the making, Trevor Giles, utilities superintendent for the town of Dillon Water Department, said Wednesday.
The arrival of the trout is an important step toward rehabilitating the water system, Giles said, but the plan was to introduce the popular sport fish several years ago.
But in 2008 Colorado engineer’s ordered the reservoir be drained, citing beetle-killed trees that affected the stability of the downstream slope and the deterioration of the metal-pipe spillway. At that time Dillon officials immediately began seeking funds for the $6.4 million project that would include enlarging the existing reservoir from 62 acre-feet to 288 acre-feet, or 2 million gallons to about 10.5 million gallons, as well as multiple structural improvements.
In June, Old Dillon Reservoir Authority officials began refilling the reservoir in preparation for the introduction of the trout, Giles said. The golden trout eggs were acquired from California wildlife officials through a trade agreement with Colorado wildlife managers. They were raised, beginning in 2011, at Colorado Parks and Wildlife’s Rifle Falls Fish Hatchery in Rifle.
Old Dillon Reservoir is just one of several Colorado lakes identified that could produce a vibrant brood of California golden trout, Giles said. Although it will take several years before the experiment is deemed a success, Giles said he noticed a lot of positive signs Tuesday when the first population of fish were introduced into Old Dillon Reservoir.
“The fish went straight down to the rocks to find shelter, which is a good sign because a lot of hatchery-raised fish will stay near the surface because they’re used to being hand fed,” Giles said. “After they found shelter they started hitting caddis flies and nymphs floating on the water.”
John Ewert, fish biologist with Colorado Parks and Wildlife, “was really excited because we just started filling the reservoir in June and we weren’t expecting there to be so much bug life in the water after just six weeks,” Giles added.
Old Dillon Reservoir and Colorado Parks and Wildlife officials plan to monitor the first stocking of golden trout during the course of the next several days in hopes of adding 4,000 more fingerlings in about two weeks. If the youngsters take to their new home, a third stocking of up to 5,000, 7- to 9-inch golden trout could be added to Old Dillon Reservoir in September, Giles said.
“We plan to build the site as an angler destination,” Giles said. “We believe it will be a viable fishery beginning immediately after the final stocking in September.”
Although anglers seeking to add golden trout to their list of Colorado conquests don’t have to wait much longer, those hoping to transfer their catch to the dinner table will have to exercise more patience.
California golden trout typically grow one to two inches annually and don’t reach sexual maturity until they are 14 to 16 inches long, Giles said. It could take up to five years before Old Dillon Reservoir’s new inhabitants begin to spawn and the golden trout population is deemed self-sustaining.
Until then fishing will be catch and release and anglers will be restricted to artificial flies and lures only, Giles said. Those regulations may change several years down the road to permit the taking of golden trout larger than 16 inches.
Golden trout are the official state fish of California and native to Golden Trout Creek in the southern Sierra Nevada Mountains.
Goldens are a subspecies of rainbow trout and, like Colorado’s native cutthroats, they will hybridize with their rainbow cousins.
Though highly sought after for their fighting ability, which is arguably rivaled only by the cutthroat, goldens tend to butt heads with brook trout and will struggle in competing environments.
Upgrades to Old Dillon Reservoir turned out to be a blessing in disguise, Giles said, because officials would not have been able to introduce the new species to Summit County had the reservoir not been drained.
“This is very exciting to be able to have this opportunity,” Ewert said. “There aren’t too many places where there aren’t competing species.”
Old Dillon Reservoir is located 2.4 miles south of the town of Dillon between Interstate 70 and Dillon Dam Road. A ¾-mile trail to the reservoir may be accessed from Dillon Dam Road just north of Heaton Campground.
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