Brief by Central Staff
Wildlife – July 2003 – Colorado Central Magazine
Colorado’s long drought — which may or may not be over — may have damaged fishing in most of the state, but it has helped the brown trout in the Arkansas River as it courses through the mountains.
That’s the word from the Colorado Division of Wildlife: “Low, clear stream flows created a bonanza of bugs for the trout to feed on and lack of runoff lengthened their feeding summer, growing larger, healthier, and more fish for anglers to enjoy.”
What hurts trout most during low water times is heat — shallow pools that get too warm. But the Arkansas generally flows through a narrow channel without those shallow pools. It is fed by melting snow from Colorado’s highest peaks; summer night temperatures are usually cool; and when the water does get too warm, the fish can escape to deeper pools and shaded banks.
Thus the brown trout thrived last summer, even though water temperatures reached into the 80s in riffles near Parkdale (the upper end of the Royal Gorge). “We never saw any visible signs of stress in the fish, let alone a die-off,” said Greg Policky, aquatic biologist for the Colorado Division of Wildlife.
He pointed out that the low flows last summer — 250 to 400 cfs, down from the usual 750 July and August flow — provided optimum trout habitat. This spring’s spawning showed a doubling of “trout biomass,” as well as eight times as many browns over 14 inches long.
As for this year, summer flows might be relatively low because upstream reservoirs need to be filled, and it could be another good year for trout.
But the peak runoff in early June remained a major variable as this edition went to press. Our spring weather was even more fickle than usual, with warm sunny days followed by chilly days of drizzle.
Policky said the best pattern for the fish would be a stretch of warm weather creating a strong, short-term run-off, since “a quick blast of water down the basin would wash down much of the sediment collected on the river bottom and would allow the fish to begin feeding earlier and give them a longer foraging season through the summer.”