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Source: NIWA – National Institute of Water and Atmospheric Research

What are the threats?

There are several factors that may be causing a decline in kākahi populations.

Habitat loss and change

Changes to the natural environment can impact kākahi habitat. This includes the introduction of invasive fish, aquatic plants and rats.

Loss of vegetation-shading streams may increase water temperatures and changes to water flows may reduce kākahi habitat. Less water may dry out habitat, increase water temperatures, and allow smothering algal growth. Sudden increases in water flows can scour away the sandy places where kākahi live.

Pollutants such as excess nutrients, heavy metals, pesticides and sediments can kill kākahi. Juvenile kākahi are especially sensitive to contaminants.

Loss of host fish

The decline of native fish species which are a host for the larval/glochidia phase of the kākahi life cycle, can decrease juvenile production in kākahi populations.

What can you do to help?

The current conservation status is “At Risk” or “Threatened”.

With more information we will be able to better track kākahi populations, and come up with new ways to protect them. If you come across kākahi, please keep records of your observations to the best of your ability by recording:

  • Location (GPS)
  • Estimate of abundance
  • Size and condition
  • Species
  • Habitat

All observations can be submitted to the Freshwater Fisheries Database


Taonga Species Series