#Dillon, Colorado.
Dillon Reservoir is one of just two places in the country’s lower 48 states home to a trophy fish called Arctic char, and after years of stocking, Colorado Parks and Wildlife report that the fish are doing well.
Based on his biennial fish survey last summer and accounts from local anglers, Parks and Wildlife fisheries biologist Jon Ewert said the char seemed to have reached a critical mass and their success may signal a turning point in the improvement of the reservoir as a fishery.
“Over the course of the past year is when this fishery has really taken off finally,” said Ewert, who works in Summit and Grand counties as one of 18 CPW fisheries biologists.
Bob Evans, longtime manager of the Dillon Marina, agreed and credited the improvement to Ewert’s work.
“I’ve never seen the ice fishing and the fishing in Dillon as good as it has been this year and last year,” Evans said, “and it seems to be getting better every year.”
Now that a recent study proved the fish are successfully reproducing in the reservoir, Parks and Wildlife reduced the bag limit for anglers in hopes of growing the Arctic char population.
Effective Wednesday, April 1, the new rule lowers the daily bag and possession limit of Arctic char to one fish 20 inches or longer. Anything smaller must be immediately release. Currently, the bag limit is four Arctic char of any size.
“By the time they get to 20 inches in size they will have at least a couple opportunities to spawn before they’re available to be harvested,” Ewert said.
The agency’s goal is to be able to stop importing Arctic char eggs from Canada, raising them in hatcheries and stocking them once the population is self-sustaining.
Summit County anglers and fishing outfitters have been supportive of the new limit.
“It’s essential to preserve those fish,” said Nate Crawford, who runs Big Ed’s Fishing Ventures in Dillon. “They’re a gem to us. If we catch one it’s a gem.”
A RARE PRIZE FOR SUMMIT ANGLERS
Like rainbow or brown trout, Arctic char have spots dotting their bodies. The char’s spots, however, are lighter in color than the rest of their bodies.
Arctic char look most similar to brook trout, which are colorful fish with pink spots surrounded by blue halos.
“Arctic char have pink- or peach-colored spots, but they do not have any halo,” Ewert said.
They can also be most easily told apart, especially by an angler watching from above the surface, by their lack of squiggly lines, or vermiculations, on their dorsal fins.
Besides Summit County’s largest reservoir, a reservoir in Maine is the only other place in the U.S. anglers can find Arctic char.
“It’s something that people can’t find anywhere else,” Ewert said, and because the char are a cold-loving fish adpated for deep lakes, Dillon Reservoir provides a rare suitable habitat. “It’s a perfect match.”
Anglers have been most successful catching the char while ice fishing and using small jigs in less than 60 feet of water, though some summer catches have been reported.
Arctic char were introduced to the food chain after biologists realized mysis shrimp were taking over Dillon Reservoir.
The tiny shrimp were added in the 1970s to encourage brown trout growth, inspired by a lake in British Columbia where freshwater shrimp were the massive trout’s food source.
But unlike in British Columbia, Dillon Reservoir currents don’t cause the two species to interact. Brown trout feed during the day while the bottom-feeding shrimp hide. Then they switch places at night, and the shrimp compete with the trout for zooplankton food.
“They keep trying to do something to fix something,” said Jackson Streit, owner of Mountain Angler in Breckenridge. “It’s not a perfect science.”
Streit moved to Summit in the 1970s and said the fishing in Dillon Reservoir has dropped off dramatically since then.
To improve the reservoir’s recreational qualities, Parks and Wildlife stocked Arctic char sporadically in the 1990s and then every year since 2008.
Ewert said he stocks about 20,000 4-inch-long Arctic char a year in the reservoir.
He also adds roughly 300,000 fingerling rainbow trout each year, from 3 to 5 inches long, as well as close to 30,000 rainbows that are catchable size of 10 inches long.
From 2012 to 2014, a Colorado State University student named Devin Olsen studied the population to find the answers to two simple questions.
“No. 1, are they doing a good job eating mysis shrimp, and No. 2, are they reproducing on their own in Dillon Reservoir,” Ewert said.
Olsen found definitive yeses in his research, which showed not only that the fish were going down deep and eating the shrimp but also that a significant amount of the fish he handled, about a third, had been hatched in the reservoir.
He was able to prove that last point, Ewert said, by dissecting the fish and looking at the chemical composition in a bone similar to the human inner ear. Because their aquatic habitat it different, fish hatched in the hatchery have an easily distinguishable different chemical composition than those hatched in the reservoir.
“There’s no doubt where that fish came from,” Ewert said.
‘ALL FOR IT’
For the last 10 years, Ewert has conducted a netting survey at Dillon Reservoir. He sets up large nets at the bottom of the lake in the same six locations at the end of June, as close to the same date as possible in even-numbered years, and leaves them overnight.
For the first time, he captured Arctic char in 2014 in all six areas of the reservoir, he said, “so they’re everywhere in the lake.”
He caught 14 char ranging from 8 to 18 inches in length, and he determined the char made up 4 percent of the reservoir’s overall fish population.
The most common fish in Dillon is white sucker, a non-sport fish Ewert compared to a weed, which made up 66 percent of the fish species in 2014, down from 76 percent in 2012.
The next most populous fish in 2014 were brown trout, at 17 percent of the fish species, followed by Kokanee salmon at 8 percent and rainbow trout at 4 percent.
This summer, Ewert will survey char specifically with targeted deep water netting to learn more about the population and the fish behavior.
At Cutthroat Anglers in Frisco, fishing guide Kory Lewis said the new limit won’t negatively impact business, as the limit for other trout hasn’t changed, and could be a positive if attention on Arctic char attracts more anglers to the area.
“I’m definitely all for it,” he said. “They’re a really good eating fish.”
Ewert said through the six-month process of changing the regulation, one person contacted him upset about not being able to take home the rare, large Arctic char.
“But the fact is there’s a developing population,” Ewert said, “and fish over 20 inches might be scarce now, but they’re going to become more and more common.”
Perhaps five years from now, he added, the agency will loosen the rule and allow anglers to take more Arctic char home.
“Regulations don’t have to stay etched in stone forever,” he said. “They’re a tool that you apply to help the population improve in a way that you think it will, and then [you] reassess, give it at least five years and see what the effect is then.”
Courtesy of the Summit Daily News.
