Setting the Stage
About the McKenzie River
The McKenzie is a unique river. A 90-mile long tributary of the Willamette, it begins as a spring-fed river in the high Cascades at Clear Lake. It tumbles down through a steep upper section filled with treacherous rapids. After about 20 miles, the canyon turns west and opens up into a valley, where it flows another 70 miles to the confluence with the Willamette north of Springfield. The communities of Eugene and Springfield depend on the McKenzie for high-quality drinking water, and their citizens enjoy the recreational opportunities the river offers. The river is home to populations of rainbow trout, cutthroat trout, bull trout, spring chinook salmon, as well as a number of non-game species.
Oregon’s McKenzie River – A Battleground?
It may have seemed so for most of 2009 and early 2010, as a heated debate raged in the angling community regarding stocking of catchable rainbow trout in the McKenzie.
Since 1950, the Oregon Department of Fish & Wildlife had planted approximately 140,000 catchable hatchery rainbow trout annually in the McKenzie. In the early 1980s, the lower 19 miles and upper 22 miles of the river were designated as wild trout conservation areas, thus limiting hatchery trout stocking to a 35-mile section of the middle McKenzie. This middle section was managed as a consumptive, put-and-take fishery. By regulation, wild trout were required to be released unharmed. Creel surveys in 1973, 1974, and 1983 showed that despite this regulation, very few wild trout were being caught in the stocked section of the McKenzie. Other than creel surveys, the Department of Fish & Wildlife had little data on the status of the river’s wild rainbow trout population. There had been no formal study as to why wild rainbow trout were scarce in the stocked section, though the Department’s 1988 McKenzie Management Plan pointed at a potential cause: “Competition between hatchery and wild trout and angling pressure generated by the releases of hatchery trout will continue to suppress wild trout production below its potential.”
A Small Victory
In late 2008, a vocal group of local anglers opined that the practice of stocking hatchery trout in the middle section of the river should be curtailed or eliminated due to its negative effects on the wild rainbow trout population. Their concern focused on the health of the wild rainbow trout population in the middle McKenzie – primarily the portion between Hayden Bridge (river mile 19.0) and Leaburg Dam (river mile 40.0). Prompted by concerns over the health of the McKenzie River’s wild trout population, the Oregon Department of Fish and Wildlife (ODFW) discontinued trout stocking in a 5.1 mile section of the McKenzie (from river mile 19.0 up to river mile 24.1) in early 2010. The removal of hatchery trout from this section provided a unique opportunity to study whether the McKenzie’s wild trout populations would recover once competition from hatchery fish had been eliminated.
Competition between hatchery and wild trout and angling pressure generated by the releases of hatchery trout will continue to suppress wild trout production below its potential.1988 McKenzie River Subbasin Management Plan
The McKenzie River’s native “redside” rainbow trout is a prized catch for anglers, even though the fish has to be thrown back in.
The wild trout are generally bigger and more challenging to hook. The fish raised in a hatchery are easier to catch and can be kept and eaten.
The state says it’s well known that when hatchery fish are added to a waterway, there is a decrease in the wild population, due to competition and increased fishing.Wild Versus Hatchery Debate On The McKenzie River
That's where the Lower McKenzie Trout Population Study starts.
How much, if any, recovery would be observed after hatchery trout were removed? How quickly would it happen? What if something else entirely was limiting wild trout productivity in the McKenzie? And could a group of volunteer anglers conduct a scientific study which would provide useful data to the managing agency?
ODFW and McKenzie Guides’ Association attempt to PIT-tag and recapture wild rainbow trout to track movement. This study fails, as the group is unable to mark and recapture a sufficient number of wild rainbow trout.
ODFW conducts creel survey of McKenzie River anglers. Study indicates that anglers catch 0.39 hatchery trout per hour, 0.03 wild rainbow trout per hour, and 0.012 wild cutthroat trout per hour. This is also expressed as one hatchery trout for every 2.5 hours of effort; one wild rainbow trout for every 34.5 hours of effort, and one cutthroat trout for every 83.3 hours of effort.
ODFW conducts creel survey of McKenzie River anglers. As summarized in the 1983 study report, the 1974 creel indicates that anglers catch 0.31 hatchery trout per hour, 0.03 wild rainbow trout per hour, and 0.016 wild cutthroat trout per hour. This is also expressed as one hatchery trout for every 3.3 hours of effort; one wild rainbow trout for every 37.0 hours of effort, and one cutthroat trout for every 62.5 hours of effort
ODFW conducts creel survey of McKenzie River anglers. As summarized in the 1983 study report, the 1973 creel indicates that anglers catch 0.41 hatchery trout per hour, or 2.4 hours per fish.
The McKenzie Fish Management Plan is a part of a larger Oregon Department of Fish and Wildlife (ODFW) planning program to develop a long-term approach to conserving and utilizing Oregon’s fish resources. Basin plans, such as the McKenzie Plan, provide management direction for populations of fish in a basin. The McKenzie Plan contains policies, objectives, and actions that guide the management of fish populations in flowing waters in the McKenzie Basin. The planning process allows the public and other agencies to participate in developing ODFW management programs.
(The 1997 Plan) is a revision of the trout and whitefish sections of The McKenzie Subbasin Fish Management Plan which was adopted by the Fish and Wildlife Commission in 1988.