Video S1 - Native Cutthroat Trout and the Yellowstone Lake Ecosystem

Video S1. 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.