FAIRPLAY — The fishing has never been easier at Antero Reservoir than it is this week.
All you need is a net, fishing waders and a Colorado Parks and Wildlife uniform. A state-of-the-art fish hatchery truck doesn’t hurt, either.
Indeed, the aerated water tank on wheels is a critical component of the underway at one of Colorado’s historically most prolific fisheries. As the South Park reservoir owned by Denver Water is drained in order to repair its 100-year-old earthen dam, wildlife officials are scooping up as many of the game fish — rainbow, cutthroat, cut-bow, brown and tiger trout — as possible and moving them to nearby waters.
“It’s not necessarily something you want to do, but it’s something you need to do to take care of the resource,” said Colorado Department of Natural Resources director Mike King, who pulled on a pair of waders and joined in the fish salvage Monday. “These types of salvage operations are pretty rare. But Denver Water had a need to take care of their dam and do some improvements, so it gives us a chance to do some maintenance work at one of the premier fisheries in the state as well.”
The mission before CPW is multipronged. First the agency must sort through the fish flushing through the spillway at Antero’s eastern edge, plucking the sport fish from the thousands of white suckers that have come to dominate the fishery in recent years. Those trout will find new homes in other nearby reservoirs, while the suckers face a less-promising fate.
It’s a tricky task, calibrating water temperatures in the hatchery truck to match the outflow of the reservoir, matching the temperature again at receiving waters. The result will be a surplus of oversized fish stocked in several South Park reservoirs and some smaller, kid-friendly ponds that don’t otherwise see fish grow to more than foot or so.
“Some little kid who’s got a bobber and a worm is going to be in for the experience of a lifetime when one of these hogs latches on,” King said. “That’s going to be great.”
Then it’s Denver Water’s turn, draining the lake to a “dead pool” level of 300 to 500 acre-feet of water as work on the dam gets underway next week. If all goes as planned, the reservoir will begin to refill with snowmelt runoff as early as next spring.
Trout require at least 16 feet of water to survive the harsh winters at Antero, the uppermost reservoir in the South Platte River system. Exactly when the pool gets that deep is largely up to Mother Nature, said Travis Thompson of Denver Water.
Although CPW has little say in how quickly Antero refills, state biologists would actually prefer to see it remain empty for at least a year. That, CPW biologist Jeff Spohn says, would allow terrestrial vegetation to suck the nutrients out of lake sediment, then release them back into the water to enhance invertebrate production responsible for Antero’s renowned rapid fish growth once the pool is refilled.
The last time Antero was drained, during the drought year of 2002, terrestrial vegetation had two full summer growing seasons before the reservoir refilled, setting the stage for what evolved into Colorado’s premier lake fishery, at least temporarily.
“I would say when this reservoir is prime — meaning a scenario like 2007 to 2008, where we had perfect reservoir elevations to start managing the fishery before it actually filled and when we had a year of growth on the fish before we opened it — very few places can compare to Antero with fish growth in the Western part of the United States,” Spohn said. “Right now, this is an average South Park fishery. Growth has slowed, the survival has slowed, competition with the suckers has increased. It’s still a good fishery today, but it’s not Colorado’s No. 1 fastest trout-growing reservoir in the state right now.”
Evidence of Spohn’s assessment was seen in the nets used to gather fish on Monday, where suckers vastly outnumbered sport fish and trout size averaged a little more than 2 pounds. Relaxed bag-and-possession limits allowing fishermen to take up to eight fish for the six months before Antero’s closing this summer obviously removed several of the larger specimens, but the legendary trout that the lake is known for never materialized.
The agency would consider the transfer of 8,000-10,000 pounds of fish a good effort. Of those salvaged by Monday afternoon, the largest single trout Spohn had seen was a cutthroat-rainbow hybrid “maybe pushing 7 pounds,” he said.
“I just don’t think there’s that many big fish in here right now. In 2007, when you’re catching 16½-pound fish and a number of 10- to 12-pound fish in a day, that’s the potential,” Spohn said, adding that Antero would need to be drained every five to seven years to maintain that potential.
“It’s fun to manage this reservoir when it’s at its potential. It’s a challenge to manage it today, when it’s not at its potential, because you know it’s potential. Our hands are tied. We don’t have the ability to do what we want to do with it, because we don’t own it. But from the other perspective, if Denver Water wasn’t here, we wouldn’t have this place at all.”
Scott Willoughby: swilloughby@denverpost.com or twitter.com/swilloughby
