DOW TO STOCK MORE THAN 65 MILLION FISH THIS YEAR IN COLORADO


April 07, 2005 State hatcheries will stock more than 65 million fish this year, including 3.6 million “catchable” trout, 14.4 million sub-catchables and 46.8 million warm-water fingerlings. Reflecting improved snowpacks and stream flows in many parts of the state, the stocking schedule calls for
400,000 more catchables and 1.5 million more sub-catchable trout than were planted last year. But the stocking of warm-water species is being reduced by 7.8 million because some plains reservoirs have yet to recover from prior low-water years.

The Natural Resources Conservation Service (NRCS) of the U.S. Department of Agriculture says Colorado waters are in their best shape since the spring of 2002. Snowpacks are above average in the Rio Grande, San Juan, Animas, Dolores, San Miguel, Gunnison and Arkansas River basins and at or near average in the Colorado River basin. The only areas with below average snowpacks are up north, in the Yampa-White River basin and North and South Platte River basins.

Water storage has also improved statewide compared to last year. But some reservoirs shrank so badly during the drought it will take them several years to make up their deficits.

Catchable trout are stocked mainly in lakes and reservoirs to provide a “put-and-take” fishery in waters with little or no natural reproduction. This includes urban ponds that can support trout in the spring and fall but not in the heat of summer. Sub-catchables are stocked mainly in streams to restore native populations of cutthroat trout or buttress naturally reproducing populations of rainbow and brown trout that cannot hold their own against fishing pressure or whirling disease without help from hatcheries.

Warm-water species also need hatchery help to maintain viable populations for sport fishing. Popular hybrids such as wipers, a cross between white and striped bass, and saugeyes, walleyes crossed with saugers, cannot reproduce and must be stocked. Other warm-water species
such as walleyes, bass, crappie and catfish can reproduce naturally but must be supplemented by hatchery fish to compensate for fluctuating reservoir levels, water temperatures and water quality.

Whether it’s trout or bass, said Robin Knox, the DOW’s sportfishing coordinator, “all stocking decisions are made by biologists based on management requirements and water conditions.” And warm-water fish, which are stocked as fingerlings or fry, have to be planted in much greater numbers than trout because they only have a 1-10 percent chance of surviving enough years to reach catchable size.

One exception last summer was the stocking of 4,000 channel catfish between 12 and 14 inches in size along the Front Range. This was designed to give anglers better odds of catching larger fish, since catfish grow fast in warm water. Knox said more large cats will be stocked again this summer to provide fishing opportunity.

Another vital component of the warm-water stocking program is the annual collection of walleye spawn by DOW biologists and volunteers at Cherry Creek, Chatfield and Pueblo Reservoirs. The eggs are collected not only to meet Colorado’s stocking needs but also to provide a surplus for
trades with other states. This year’s goal is 75 to 80 million eggs which are used to produce both walleyes and saugeyes, created by fertilizing walleye eggs with sauger milt imported from Illinois and Kansas.

DOW biologists also report good progress in restoring three subspecies of cutthroat trout native to Colorado, once almost wiped out by competition and hybridization with non-native trout introduced to the state a century ago, drought and habitat destruction caused by human activities such as gold mining, logging and agriculture.

Cutthroat populations had dwindled dramatically before recovery efforts began in the 1970s. But the state now has 29 conservation populations of greenback cutthroats east of the Continental Divide, 76 conservation populations of Rio Grande cutts in the Rio Grande River basin and 171
conservation populations of Colorado River cutts. The development of broodstocks within the state’s hatchery system is vital to the success of this program.

“We have made extraordinary progress,” said DOW Senior Fish Biologist Sherman Hebein.

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