Crater Lake does have fish, though their presence is not natural. The fish currently inhabiting the lake were introduced through human efforts, beginning over a century ago to enhance recreational opportunities.
Crater Lake’s Natural Fish-Free State
Crater Lake was originally devoid of any native fish species until 1888. Formed approximately 7,700 years ago from the collapse of Mount Mazama, the deep caldera filled with precipitation, creating a lake isolated from external water sources. This isolation meant no streams or rivers connected the lake to other fish-bearing waters, preventing natural colonization. The lake’s depth, pure, cold waters, and limited food sources created an environment naturally inhospitable to many fish species.
The Human Hand in Fish Introduction
The introduction of fish into Crater Lake began in 1888, spearheaded by William G. Steel. Stocking efforts continued regularly through the early 20th century, ceasing in 1941 once introduced fish populations were self-sustaining. Approximately 1.8 million fish, comprising six different species, were introduced.
Initial stockings included rainbow trout, with subsequent introductions of brook and brown trout, steelhead, and coho (silver) salmon. However, only rainbow trout and kokanee salmon, a landlocked form of sockeye salmon, successfully established lasting populations. It is believed that kokanee salmon were inadvertently introduced when silver salmon fingerlings were stocked.
Present Day: Fish Populations and Fishing
Rainbow trout and kokanee salmon are the two dominant introduced species thriving in Crater Lake. Kokanee salmon are generally more abundant, with estimates ranging from 60,000 to hundreds of thousands, typically measuring around 8 inches but sometimes reaching 18 inches. Rainbow trout are less numerous but often larger, averaging 10 to 14 inches, with some specimens recorded up to 26 inches long and weighing 6.5 pounds. Both populations are stable and self-reproducing, with kokanee feeding on zooplankton and rainbow trout consuming aquatic insects.
Crater Lake National Park encourages fishing for these non-native species, requiring no fishing license within park boundaries. To protect the lake’s ecosystem, anglers must use only non-organic artificial lures or flies; organic baits, such as worms or fish eggs, are strictly prohibited. There are no size or catch limits for rainbow trout or kokanee salmon caught from the lake.
Access for fishing is limited to the shoreline at Cleetwood Cove and from Wizard Island docks when boat tours are operating. Private boats, waders, and wetsuits are not permitted in the lake, and fishing is restricted within 200 feet of boat docks. Additionally, certain streams within the park, like Sun Creek and Lost Creek, are closed to fishing to protect native bull trout, a threatened species.