• Wizard Island

    Crater Lake

    National Park Oregon

Monitoring the Fish of Crater Lake

Rainbow trout from Crater Lake

A Rainbow Trout caught in Crater Lake.


Crater Lake contains kokanee salmon and rainbow trout

  • the introduction of these fish is the greatest human impact on Crater Lake
  • Kokanee exhibit a boom and bust cycle in abundance over about a ten year
    • when the kokanee are abundant certain zooplankton become scarce due to predation
    • the kokanee "eat themselves out of house and home"
  • kokanee vary widely in size and maturity during the boom/bust cycles
    • when the zooplankton prey is scarce size is reduced and fewer reach maturity

Did You Know?

Did You Know?

The Clarks Nutcracker is frequently seen around the rim of Crater Lake. It feeds almost exclusively on the seeds of the Whitebark Pine. It gathers the seeds and hides some of them to eat later, helping the tree to disperse its seeds. Forgotten seeds may grow into new Whitebark Pines.