The Carson–Iceberg Wilderness supports a native population of the only
Paiute cutthroat trout in existence in the drainages of Silver King Creek, a tributary of the East Fork Carson River. They were listed as endangered under the Endangered Species Preservation Act of 1966 and upgraded to threatened status in 1973 with the passage of the
Endangered Species Act (ESA) which allowed regulated fishing of the Paiute. Historically, the
US Fish and Wildlife Service believe the Paiute trout only occupied the Silver King Creek and its tributaries below the barrier of LLewellyn Falls, and around 1912 were introduced to other streams where the Paiute hybridized with the Lahonton and rainbow trout species. The "revised recovery plan" by the US Fish and Wildlife Service seeks to remove nonnative fish from the environment, protect habitat for the current populations of Paiute trout, both within the historical range of the Silver King Creek watershed and the other streams in the region, such as North Fork Cottonwood Creek, and lastly, to study the Paiute trout to better understand the population trends. The main distinguishing characteristic is the lack of spots on the body. The closely related
Lahontan cutthroat trout has between 50 and 100 spots whereas the Paiute may have up to nine, but rarely more than five. The Paiute trout require a habitat of clean, well-oxygenated, moving water with gravel bottoms and quiet pools near riparian zones. They reach maturity in 2 years, spawn during June and July with eggs hatching in 6–8 weeks and the fry emerging from the gravel in 2–3 weeks. The rate of growth depends on water temperature and food access, with the Silver King Creek Paiute having been measured at 13.5 inches. Predators include the water shrew and the dipper, a bird that can go underwater to feed. Humans impact the Paiute trout as the fish show a lack of wariness to anglers, possibly because of the high elevation environment and lack of predators. Serious population declines have occurred from moderate to light fishing of the trout. Also in the Silver King Creek watershed are the
Sierra Nevada yellow-legged frog,
mountain yellow-legged frog and the
Yosemite toad. ==Permits==