Millions of trout and salmon, from scrappy catchable-sized rainbows to fingerlings that can grow to catchable size, will be stocked in lakes and streams throughout the state this spring and summer.
But some high-country reservoirs will receive fewer trout than last year because Division of Wildlife biologists want to further reduce the chance that whirling disease could affect any of the state's self-sustaining wild trout populations. Many of the trout available for stocking come from state hatcheries infected with the parasite that can cause whirling disease.
"Our hatchery workers have been bringing fish to lower elevation areas for more than a month now, and the pace is going to pick up dramatically over the next few weeks," said Eric Hughes, the DOW's fish production manager.
All told, the DOW will stock more than 3.8 million catchable-sized trout averaging 10 inches in length and more than 13 million fingerling-sized trout and salmon.
"It's going to be especially important for anglers to check the division's weekly fishing and stocking reports this year to see where we've stocked the most fish and where fishing is good," said Steve Puttmann, the DOW's aquatic manager in northeastern Colorado.
"We're going to have great fishing through the spring and summer at some of the state's most popular waters," added Doug Kreiger, aquatic manager in southeastern Colorado.
The decision to bring more trout to lower elevation waters is the result of new DOW research showing that the stocking of fish lightly exposed to whirling disease may affect populations of wild trout downstream, even though the water already contains the parasite. DOW researcher Barry Nehring's work strongly suggests that adding additional spores can increase infection downstream under some conditions.
Whirling disease is a parasitic infection native to Europe that causes debilitating deformity in some trout.
The DOW is in the midst of a $12 million hatchery renovation project intended to rid key hatcheries of the parasite.