The price for fishing permits in Yellowstone National Park will double this year from $10 to $20.
The park has also replaced its seven-day permit, which sold for $5, and replaced it with a 10-day permit that will cost $10.
The National Park Service said the fee increases will help the park meet increasing costs for fisheries management, such as the cost of controlling illegally introduced lake trout in Yellowstone Lake. The Park Service first began charging in 1994.
Park spokeswoman Cheryl Matthews said controlling the lake trout population in Yellowstone Lake costs the park $300,000 a year. Lake trout are threatening the native cutthroat trout population.