Yellowstone Lake Ecosystem Restoration: A Case Study for Invasive Fish Management
Externally hosted supplementary file 1
Description: Video S1. Native Cutthroat Trout and the Yellowstone Lake Ecosystem. The Yellowstone Lake ecosystem in Yellowstone National Park. Following glacial recession, cutthroat trout evolved as the sole salmonid and dominant fish within Yellowstone Lake and its connected river network. Yellowstone Lake is a large aquatic system on the Yellowstone Plateau (2,357 m in elevation) with a highly protected watershed (> 3200 km2) located within Yellowstone National Park and the Bridger-Teton Wilderness of Wyoming, USA. Powerboat access is limited to only two locations, and most of the shoreline lies in protected (federally proposed) wilderness. Thermal structure of the lake is typically unstable with a weak and variable thermocline at a depth of 12–15 m during July-September. Surface water temperatures rarely exceed 18°C. The lake freezes over by late December and can remain frozen until late May or early June. In winter, ice about 1 m thick covers much of the lake except where shallow water covers active hot springs. During spring (May-July), cutthroat trout spawn in tributaries around Yellowstone Lake, where they are important prey for grizzly bears, black bears, river otters, and numerous avian predators.
Externally hosted supplementary file 2
Description: Video S2. Gillnetting Invasive Lake Trout. Gillnetting suppression of invasive lake trout in Yellowstone Lake. Apex predatory lake trout, discovered in 1994, invaded Yellowstone Lake and caused a precipitous decrease in abundance of native cutthroat trout. Lake trout are a deep-water dwelling, cold-adapted (< 10°C) predatory species that do not serve as an ecological substitute for cutthroat trout in Yellowstone Lake. Gillnetting suppression efforts were initiated in 1995 and were increased to an effort level achieved in 2012 that led to a reduction in lake trout biomass. Contracted and U.S. National Park Service crews using specialized boats and equipment process > 2,500 km of gillnets annually. Several hundred thousand lake trout carcasses are deposited to deep (> 65 m) regions of the lake. Research is ongoing to document potential affects of carcass deposition on the ecology of Yellowstone Lake.
Externally hosted supplementary file 3
Description: Video S3. Organic Pellet Application to Carrington Island Spawning Site. Suppression of invasive lake trout by treatment of spawning sites with organic pellets to kill embryos in an IPM approach. Because only a few weeks are available to safely work on Yellowstone Lake following the peak of lake trout spawning each autumn, we expanded the embryo suppression research to include a comprehensive treatment of a spawning site with organic pellets by helicopter (with long line and seeder/spreader) to better understand the logistical constraints that may be faced when attempting large-scale, multi-site applications in the future. Dr. Christopher Guy of the USGS Montana Cooperative Fishery Research Unit describes the Carrington Island spawning site. During an October 2019 experimental treatment, all of the rocky substrate at this spawning site (0.5 ha) was treated with 18,000 kg of organic (soy and wheat gluten) pellets in less than one day. The pellets induce organic decomposition and decline in dissolved oxygen concentration, which is lethal to lake trout embryos, curtailing recruitment from the site. Relative to the expansive lake areas intensively gillnetted over a 22-week season (> 60 km of gill nets set daily), lake trout embryo suppression targets relatively small sites during a period of 2–3 weeks in autumn where the majority of a future year class is concentrated. Broad-scale application of pellets in autumn may reduce lake trout recruitment and enhance population suppression as part of an IPM approach targeting multiple lake trout life stages because the area of the 14 verified spawning sites is only 11.4 ha (0.03% of lake surface area).
Externally hosted supplementary file 4
Description: Video S4. Angling for Restored Native Cutthroat Trout. Yellowstone cutthroat trout recovery results in large adults returning to tributaries of the upper Yellowstone River to spawn. Sustained gillnetting suppression of invasive lake trout is allowing for a recovery of native Yellowstone cutthroat trout. Although abundances remain below target levels, the relative weights (condition) of cutthroat trout have increased, large individuals (400+ mm) are more prevalent, and individual weights have more than doubled over the past four decades. Cutthroat trout from Yellowstone Lake make long-distance (> 40 km) spawning migrations upstream from Yellowstone National Park and into the remote headwaters of the upper Yellowstone River in the Bridger-Teton Wilderness, Wyoming, USA. Here, Liz Storer, Wyoming Storer Foundation and Jason Burckhardt, Wyoming Game and Fish Department are fly-fishing for the migratory cutthroat trout in Atlantic Creek during early July, 2019. The cutthroat trout transport lake-derived nutrients into these remote headwaters in U.S. Forest Service lands, highlighting the importance of large, unfragmented, highly protected watersheds such as those of Greater Yellowstone. Partnerships with the Storer Foundation, the Wyoming Game and Fish Department, and numerous others developed over the past 25 years were the driving force behind the initial recovery of cutthroat trout and restoration of this ecosystem.
Koel, T.M.; Arnold, J.L.; Bigelow, P.E.; Brenden, T.O.; Davis, J.D.; Detjens, C.R.; Doepke, P.D.; Ertel, B.D.; Glassic, H.C.; Gresswell, R.E.; Guy, C.S.; MacDonald, D.J.; Ruhl, M.E.; Stuth, T.J.; Sweet, D.P.; Syslo, J.M.; Thomas, N.A.; Tronstad, L.M.; White, P.J.; Zale, A.V. Yellowstone Lake Ecosystem Restoration: A Case Study for Invasive Fish Management. Fishes 2020, 5, 18. https://0-doi-org.brum.beds.ac.uk/10.3390/fishes5020018
Koel TM, Arnold JL, Bigelow PE, Brenden TO, Davis JD, Detjens CR, Doepke PD, Ertel BD, Glassic HC, Gresswell RE, Guy CS, MacDonald DJ, Ruhl ME, Stuth TJ, Sweet DP, Syslo JM, Thomas NA, Tronstad LM, White PJ, Zale AV. Yellowstone Lake Ecosystem Restoration: A Case Study for Invasive Fish Management. Fishes. 2020; 5(2):18. https://0-doi-org.brum.beds.ac.uk/10.3390/fishes5020018Chicago/Turabian Style
Koel, Todd M., Jeffery L. Arnold, Patricia E. Bigelow, Travis O. Brenden, Jeffery D. Davis, Colleen R. Detjens, Philip D. Doepke, Brian D. Ertel, Hayley C. Glassic, Robert E. Gresswell, Christopher S. Guy, Drew J. MacDonald, Michael E. Ruhl, Todd J. Stuth, David P. Sweet, John M. Syslo, Nathan A. Thomas, Lusha M. Tronstad, Patrick J. White, and Alexander V. Zale 2020. "Yellowstone Lake Ecosystem Restoration: A Case Study for Invasive Fish Management" Fishes 5, no. 2: 18. https://0-doi-org.brum.beds.ac.uk/10.3390/fishes5020018