From Wyoming Game & Fish
Harrington reservoir was filled in 1994 and by the late 1990s was well on its way to becoming the premier bass fishery in the Big Horn Basin.
However, since the introduction of Yellow Perch, the story at Harrington is one that has played out numerous times in the western U.S. The story goes like this…..The initial perch find favorable conditions and grow fat and fast. Anglers respond by digging out augers, bobbers, and fried fish recipes. For a short period of time all is well. Then the perch which lack a efficient predator in the lake start to reproduce in mind boggling numbers. The average female Yellow Perch produces 23,000 eggs each year and large individuals can produce more than 50,000.
Anglers can’t keep up with such reproduction and soon the food utilized by perch (and many of the other fish) becomes limited and the fishery rapidly declines to one dominated by perch that are too small to attract anglers. Unfortunately small perch don’t stop reproducing and without a significant change in the physical or biological structure of the lake a “stunted perch lake” remains a “stunted perch lake”. So how will the story end for Harrington?
At Harrington, we had two options for changing the biological structure of the lake: (1) chemically remove all fish and start over or (2) introduce an effective perch predator.
Without question both of these options are risky and the outcome is far from certain. However the introduction of a predator could mean a reduction in the “down fishing within a couple of years as opposed to five or more years that would follow a chemical treatment. Because of this (and a host of other nasty details that come with chemical treatment) it was decided that walleye would be stocked into the reservoir.
Walleye co-evolved with yellow perch and are voracious perch eaters. However, how many walleye to stock into a “stunted perch lake” is a topic of debate. Examples from other states have shown that adding too many walleye to a stunted perch population can tip the balance towards the predator in such a way that perch are all but eliminated and the walleye don’t grow large enough to provide quality angling.
Further complicating the matter is that yellow perch are also predators of small walleye. Because of these problems it is difficult to determine how many stocked walleye a “stunted perch lake” such as Harrington can sustain.
The good news in the Harrington saga is that walleye have already been stocked in the reservoir (2,795 in 2003) and that once these fish reach a size that they can consume perch they will grow fat and fast leading to some plump walleye to be caught. The bad news is that for the immediate future Harrington’s bass and bluegill fisheries probably won’t be much better than they have been.
The number of walleye stocked will be increased to 18,400/year for the next three years as we evaluate their survival and the impacts to the perch population. Walleye fishing probably won’t be worth your time at Harrington until 2005. Meanwhile, there are still some very nice bass in the lake and 25,000 bluegill were stocked in 2003.