March 14, 2008

Has Frog Conservation Impacted Sierran Trout Fisheries?

There are a plethora of stories floating around the print media and the internet decrying the impact of mountain yellow-legged frog conservation efforts on Sierra Nevada trout fisheries. The on-the-ground realities paint a markedly different picture. In fact, one of the most remarkable outcomes of the increased research and management interest in mountain yellow-legged frogs is that backcountry trout fisheries are better managed today than they have been in decades.

With all due respect to the many capable biologists at the California Department of Fish and Game (CDFG), the CDFGs management of backcountry waters has been haphazard at best. Until recently, millions of fingerling trout were stocked into thousands of lakes every summer using airplanes, without any consideration given to whether those introductions were actually necessary to maintain trout populations. Fish population surveys that would have provided information on what stocking level, if any, was appropriate, were rare to nonexistent. This data-free management led to hundreds of lakes being stocked repeatedly despite the fact that the majority of these lakes harbored self-sustaining trout populations. When the CDFG halted the stocking of some of these self-sustaining trout populations, the populations showed no change in trout density and actually showed slight increases in fish size (see
2004 paper authored by Armstrong and Knapp in the Canadian Journal of Fisheries and Aquatic Sciences - available here). So, for years the CDFG was essentially just throwing many of those fingerling fish away. At a cost of $0.25-0.50 per fingerling, this resulted in the waste of millions of dollars.

After ignoring backcountry waters for more than 50 years, the decline of the mountain yellow-legged frog finally forced the CDFG to take Sierran lake management more seriously. Under the leadership of biologists like Curtis Milliron, the CDFG recently undertook a detailed inventory of thousands of lakes and as a result finally had the data necessary to make science-based stocking decisions. Although the backcountry lake stocking program remains archaic in many respects, the CDFG has at least taken a very important step in the right direction. However, it is important to remember that concern over the mountain yellow-legged frog drove these management changes, changes that have benefitted Sierran trout fisheries.

I still think that the CDFG has some important lessons to learn from Sequoia, Kings Canyon, and Yosemite National Parks. These parks terminated all fish stocking within their borders in the early 1990s, and anyone who has spent time exploring these park lakes knows that the majority of previously-stocked lakes continue to provide outstanding angling opportunities, all at no cost.

Sometimes the best things in life are in fact free....

Back to The Mountain Yellow-legged Frog Site.

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