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

Last updated: February 28, 2015

Contact the Park

Mailing Address:

Crater Lake National Park
PO Box 7

Crater Lake , OR 97604


(541) 594-3000

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