The lake, now known as Surprise Lake, is 32 river miles from the ocean, but lies at over 1,000 feet in elevation. Sockeye salmon accessed Surprise Lake at some time since the flood and established spawning populations there, persisting despite an eruption in 1931, which dumped six feet of volcanic material into the lake. In this first year of inventory, the project successfully identified and sampled three spawning populations. Two of the spawning populations are in the caldera and one is downstream at Albert Johnson Creek, a major tributary to the river. Initial results from body size and shape measurements suggest limited mixing among the two populations sampled within the caldera.
Genetic analysis is pending.
In addition to sockeye salmon populations, the project obtained the first documentation of chinook salmon in the Aniakchak River drainage. Future study plans include completing characterization of the identified populations and their habitats, and additional efforts to identify more spawning populations at sites in the caldera and in Aniakchak River itself. This baseline information is especially critical because these populations are subject to commercial harvest outside and subsistence harvests inside the unit boundaries. This project is supported and carried out by the National Park Service. It will provide a foundation of population information to ensure protection of sockeye salmon populations in Aniakchak National Monument and Preserve.