Lake trout (Salvelinus namaycush) have invaded the waters of Yellowstone National Park. They are disturbing the existing wildlife. The diet of the trout has affected zooplankton, river otters, osprey, bald eagles, bears, elk, and the cutthroat trout. The most affected was the native trout. The invasive trout started feeding on the native cutthroat trout. With the decline in cutthroat trout numbers, the presence of zooplankton increased, making the lake water clearer and its temperature warmer. Lake trout live in depths inaccessible to other animals. Since they're eating a good chunk of the cutthroat trout population, many of the predators are finding themselves with less food to eat. The population of ospreys and bald eagles has decreased, while otters shifted their diet to longnose suckers and amphibians. Even black bears and grizzly bears needed to find alternative food sources due to the decline of cutthroat trout.

Zebra mussels (Dreissena polymorpha) have also invaded Yellowstone National Park. They are native to Eastern Europe and western Asia. It is believed they were brought here by boats. Zebra mussels have drastically impacted many ecosystems. These creatures consume significant biomass of phytoplankton, depleting the foundation of the aquatic food web. They have extreme diets and multiply really quickly. And they don't just damage ecosystems, mussels can cause severe infrastructure and economic damage by blocking water supply pipes of power and water treatment plants, irrigation systems, and industrial facilities.