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 Back to Chapter 5: Managing Risks Articles Preserving endangered night skies By Dan Duriscoe and Chadwick A. Moore Protecting American ginseng By Janet Rock Incident management team develops foot-and-mouth disease plans By Peter Dratch and Kris Fister An overview of invasive exotic plant management strategies in the Northeast By Kathleen Kodish Reeder Eradicating rats from Anacapa Island By Kate Faulkner, Gregg Howald, and Steve Ortega Other Developments Focus on toxic airborne pollutants Mosquito surveillance in the National Capital Region Award-winner Profile - Hawaii Volcanoes resource manager honored |
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 Battling alien fish in Yellowstone Lake The war against the nonnative lake trout in Yellowstone Lake escalated in 2001 when the fishery staff of Yellowstone National Park launched a new boat that more than doubles their gillnetting potential. The boat pays out 6,000 feet of net each trip. The results in 2001 were notable as operations yielded 15,496 lake trout from Yellowstone Lake. But in a body of water that covers 139 square miles and is up to 390 feet deep, reducing the lake trout population still poses a daunting challenge. Each mature lake trout can consume 50 to 90 native cutthroat trout a year, and cutthroat trout numbers have been lower in recent years than at any time during the park’s 25-year monitoring effort. This could ultimately affect 42 species of mammals and birds that feed on the cutthroat trout. Although the lake trout may have been illegally planted in Yellowstone Lake as much as 20 years ago, their presence was not confirmed until 1994, by which time they had become well established. Since 1995, gillnetting has removed more than 43,400 lake trout. Anglers also have contributed substantially in the removal, taking more than 10,000 lake trout from 1995 to 2000. In their efforts to continually improve on a strategy that will remove as many lake trout as possible while minimizing the unwanted catch of cutthroat trout, the fishery staff have had to apply the results of ongoing research on where the lake trout reside and spawn. With threats also posed by other nonnative organisms—the parasite that causes whirling disease and the New Zealand mud snail—in 2001 all of Yellowstone’s native fish species throughout the park were placed under the catch-and-release angling policy for the first time. |
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This material is from Natural Resource Year in Review--2001, published by the National Park Service, U.S. Department of the Interior, in May 2001 (publication D-2255) /YearInReview/yir/yir2001/05_risks/05_od3_alien_fish.html Last Updated: |