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Nonnative Lake Trout Result in Yellowstone Cutthroat Trout Decline and Impacts to Bears and Anglers
Author(s) -
Koel Todd M.,
Bigelow Patricia E.,
Doepke Philip D.,
Ertel Brian D.,
Mahony Daniel L.
Publication year - 2005
Publication title -
fisheries
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 79
eISSN - 1548-8446
pISSN - 0363-2415
DOI - 10.1577/1548-8446(2005)30[10:nltriy]2.0.co;2
Subject(s) - trout , fishery , salvelinus , oncorhynchus , national park , catch and release , population , ecology , geography , forage fish , fishing , biology , fish <actinopterygii> , recreational fishing , demography , sociology
During the Past Decade, Yellowstone cutthroat trout (Oncorhynchus darki bouvierO 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 horri‐ bills), use this population as an energy source, preservation of remaining cutthroat trout could be essential to maintain the integrity of the Greater Yellowstone Ecosystem.