Scientific Poster Presentation for WATS 4600 course at Utah State University, Fall 2022
Abstract
Non-native species invasions threaten the future of native fish diversity worldwide (Wilcove et al., 1998). Bear Lake is an oligotrophic natural freshwater alkaline lake on the Idaho–Utah border in the Western United States which is home to 5 endemic species, Bonneville Cisco, Bonneville Whitefish, Bear Lake Whitefish, Bear Lake sculpin and an apex predator, the Bear Lake strain of the Bonneville Cutthroat trout, commonly called the Bear Lake Cutthroat (Palacios et al., 2007). Nonnative Lake Trout were introduced to Bear Lake for sportfishing
opportunity impacting the native species through competition and predation (McHugh and Budy, 2006, Witte et al., 1992). Bear lake is limited in productivity with low densities of phytoplankton, zooplankton, and benthic invertebrate known to result in a natural bottom-up regulation of the fish communities found in lakes (Dean et al., 2009; Hayden et al., 2017). The addition of a nonnative apex predator, such at the Lake Trout, creates a top-down control on an already naturally impaired system (Albrecht et al., 2004; Koel et al., 2005; Palacios et al., 2007). While recovery efforts have brought wild Bear Lake Cutthroat back from eight percent to over 50 percent of the total population of hatchery and wild cutthroat in the Bear Lake (Tolentino, 2022), this interaction between top-down and bottom-up controls may be the limiting factor in increasing population recovery potential as well as the cause of a decrease in maximum size of the Bear Lake Cutthroat trout (Behnke, 2002). Halting programs to stock nonnative Lake Trout or pairing this action with the removal of the present fish, may result in greater success in protecting the native fish species of Bear Lake.
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