Crayfish plague

Aphanomyces astaci

If the plague reached New Zealand, it would devastate our native freshwater kōura.

About crayfish plague

Crayfish plague is caused by a water mould. It's native to North America but has spread to Western and Eastern Europe.

Why this is a problem for New Zealand

This water mould would be Armageddon to our freshwater kōura. In Europe, entire populations of crayfish have been wiped out by this plague.

As yet, no species of crayfish found outside North America is resistant to the crayfish plague.

How it could get here

The plague could arrive with crayfish, fish, or contaminated water from infected areas. It could hitchhike on equipment (such as nets, boots, ropes, clothing, or fishing gear).

MPI has strict measures in place to limit the chances of crayfish plague making it through the border.

Where would I find it?

This water mould survives only in fresh water.

How to identify crayfish plague

The most obvious sign of the plague will be the bottom of lakes, rivers, and streams covered in dead and dying crayfish.

We need a laboratory to make a definite diagnosis.

When you find possible evidence of crayfish plague

If you've found multiple dead crayfish:

  • photograph them
  • note the location and any landmarks
  • put several in a plastic bag and refrigerate them
  • call 0800 80 99 66

Note: This information is a summary of the crayfish plague's global distribution and potential impacts to New Zealand.

Last reviewed: