Non-native lake trout result in Yellowstone cutthroat trout decline and impacts to bears and anglers
Koel TM, Bigelow PE, Doepke PD, Ertel BD, Mahoney DL. 2005. Non-native lake trout result in Yellowstone cutthroat trout decline and impacts to bears and anglers. Fisheries Magazine. 30(11):10-19
During the past decade, Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) of Yellowstone Lake and its tributary streams have been affected by the introduction of lake trout (Salvelinus naymaycush), invasion by Myxobolus cerebralis (the cause of whirling disease), and drought conditions. Numbers of upstream migrating cutthroat trout at Clear and Bridge creeks have declined >90% in the past 5 years. Activity by bears has declined at spawning streams 1989–2004, and mirrored that of the cutthroat trout reductions, indicating cascading interactions in the food web of this system. Success by anglers has also declined, from two fish caught per hour in 1998 to less than one fish/h in 2004. To suppress lake trout, the National Park Service initiated a gillnetting program using up to 16 km of net each day, May–October. From 1994–2004, >100,000 lake trout were removed. The catch per unit effort and average length of spawning lake trout have declined, indicating that netting efforts may be impacting the population. As several important consumer species, including the threatened grizzly bear (Ursus arctos horribilis), use this population as an energy source, preservation of remaining cutthroat trout could be essential to maintain the integrity of the Greater Yellowstone Ecosystem.
- Type
- Journal Article
- Authors
- Koel, Todd; Bigelow, Patricia; Doepke, Philip; Ertel, Brian; Mahoney, Daniel
- Units
- YELL
- Keywords
- Greater Yellowstone Ecosystem, Invasive Species, Lake Trout, Non-Native Species, Yellowstone cutthroat trout