Crayfish locations in Crater Lake

The figure shows the locations where newts and crayfish are found in Crater Lake.
Locations in Crater Lake where Mazama Newts and Signal Crayfish are found.  Red circles represent crayfish locations and blue circles represent newt locations.  Larger circles indicate more individuals.


The figure shows the locations of newts (blue dots) and crayfish (red dots) in Crater Lake. Newts and crayfish rarely inhabit the same locations because the crayfish are aggressive and drive the newts away, or eat them.

  • Crayfish were introduced by humans in 1914,
  • Newts may have naturally colonized the lake as early as 6,000 years ago,
  • Over the past 100 years crayfish may have reduced newts distribution by 50%,
  • Crayfish may have the potential to eliminate newts from Crater Lake.

At what depth are crayfish found in Crater Lake
Figure showing the depths signal crayfish are found in Crater Lake.


This figure shows how deep signal crayfish are found in Crater Lake.

  • The deepest crayfish collected were at 820 feet!
  • 60% of the crayfish were trapped between the lake surface and 164 feet.

Why is it important to know the depths were crayfish live?

  • Park managers may want to crayfish populations to protect the Mazama Newt,
  • Knowledge of the shoreline locations where crayfish live, and how deep they live, will help managers understand the impact of crayfish to other plants and animals in the lake.

Last updated: February 28, 2015

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Crater Lake National Park
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Crater Lake , OR 97604


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