Call of the Wild for Colorado's Rivers
by Brad Lewis (Southern Rockies Restoration Project)

Each year prior to 1996, more than 15 million non-native rainbow, brook and brown trout, and non-native sub-species of cutthroat trout, were stocked in Colorado's 24,000 miles of streams. Stocking the state's streams with hatchery-raised fish - while inconsistent with the Colorado Division of Wildlife's (DOW) policy of "maintaining habitat productivity for human benefit" - has remained a long-running exception to the agency's resource management guidelines.

Stocking is recognized as a dangerous practice because it can give the false impression that ecological limits are not important. However, given the estimated million anglers with an economic impact of over $932 million vying for a chance to catch a fish in Colorado's mountain streams each year, the practice of stocking has rarely been called into question.

The negative effects of stocking streams with hatchery-raised fish are widely acknowledged by fisheries biologists. Hybridization of stocked fish with wild fish dilutes the wild gene pool. Genetic diversity is lost as hatcheries breed a limited number of strains, increasing susceptibility to disease.

Disease spreads rapidly through hatchery systems. Colorado's hatcheries experienced an epidemic of whirling disease that peaked in 1995, when 4 million fish - more than 85 percent of all hatchery stock - were infected. After these fish were released in the state's rivers, a massive population decline in the state's three native cutthroat trout sub-species (90 percent in some cases) was documented.

Hatchery life selects for competitive behavior. Surface-feeding conditions young fish to stay at or near the surface in anticipation of feeding. Released into streams, hatchery-raised fish waste their energy by trying to stay near the surface and this causes them to waste energy fighting stronger surface currents.

Wild trout shelter in protected areas, waiting for food to pass. They only rise to the surface to feed, then return to calmer water. In this way, wild fish conserve energy. Hatchery fish use more energy pursuing food than they gain. They often fight other fish, further depleting their energy reserves. An increase in hostile encounters with hatchery fish also results in weight loss and increased mortality among wild fish populations.

A Cover-up for Dying Streams

Artificial increases in fish production can conceal a fishery's decline from the public. DOW recognizes that "many of Colorado's accessible waters cannot sustain natural sport fisheries which are acceptable to the public." Without artificial stocking, many of Colorado's fisheries would collapse. This alone should indicate a serious decline in watershed health. Yet, because there are artificially high numbers of fish in the stream, the public perception is that of a "healthy trout stream."

A hatchery-based approach to fisheries management more closely resembles factory farming than natural resource management. A full 73 percent of hatchery-reared fish are caught within the first week of their release. Stocking is often timed to coincide with busy holiday weekends when fishing pressures are at their peak.

The rapid catch allows fish to be stocked in late summer, when wild trout would not otherwise survive in the warm waters of streams decimated by riparian damage, water diversions and silt loading - the downstream consequences of Colorado's mining, agricultural and timber industries.

Keeping enough water in streams to maintain stream health is not a priority under Colorado's water management policies. Fish stocking has long been used as a mitigation practice for the impacts of poor water management activities. "Over-appropriation" - i.e., excessive exploitation - of water is now the norm for many of the state's streams, resulting in extremely low seasonal flows that have, in some cases, completely dried up formerly perennial streams. Trans-basin diversions have made Colorado's streams into little more than sophisticated plumbing systems.

Habitat restoration, particularly of riparian ecosystems, has the potential to preserve instream flows and eliminate the need for stocking. In the current system, water is delivered downstream to reservoirs early in the season, where huge amounts are lost to evaporation under the southwest's intense sun. In contrast, healthy riparian ecosystems retain water, releasing it slowly as stream flows naturally drop through the summer.

With more than 90 percent of all riparian systems in degraded condition, restoration could create a vast network of "natural reservoirs," improving fish habitat at the same time.

Rechanneling River Policy

Recently, the DOW adopted a revised statewide fish management policy. The new policy, which prescribes a switch to focus on maintaining wild trout in many of the state's streams, has met with mixed reactions from the angling community. Some have suggested that angler satisfaction, not ecological integrity, should be the standard by which the success of management actions should be judged.

The DOW itself acknowledges the importance of providing a "satisfying" fishing experience, and has framed its management policy around the concept.

The Southern Rockies Restoration Project (SRRP) is working to eliminate Colorado's hatchery-based fish management policy and to educate anglers on the benefits of wild fisheries. SRRP and Trout Unlimited, have voiced support for a stronger "wild trout" policy that advocates an ecologically-based management approach.

A recent Trout Unlimited study has found numerous ecological and economic reasons to support a shift toward "wild" or "natural" fisheries management.

Changes to the current system should begin with an immediate suspension of stocking in all streams capable of supporting a naturally-reproducing wild fish population. In other streams, stocking should be suspended gradually as part of a comprehensive watershed assessment program to determine the need for stream habitat restoration.

Hatcheries are expensive to operate, diverting funds from other management activities such as habitat restoration. Closing them will release funds to allow riparian restoration to be aggressively pursued . Combined with increases in water-use efficiency, restoration would reclaim thousands of miles of streams and, at the same time, avert a collapse of Colorado's fisheries.

What You Can Do: Send comments supporting aggressive restoration and strict implementation of DOW's new wild trout management policy to: Robin Knox, Division of Wildlife, 6060 Broadway, Denver, CO 80216. For more info, contact SRRP, PO Box 1351, Boulder, CO 80306 or srrp@cris.com.