Marking inanga spawning sites beside the Avon River in Christchurch.
Image: Shelley McMurtrie | ©


Find out what you can do to help increase whitebait populations.

Why whitebait are in decline


Many of the reasons whitebait numbers are declining relate to threats and changes in their habitat.

Adult whitebait need clean water and healthy waterways to live in and breed, but in the last 100 years we have lost large areas of adult and spawning habitat due to:

  • the draining of wetlands and removal of vegetation beside streams. Whitebait use these areas for shade and protection.
  • barriers to fish passage. Barriers in waterways, like dams and overhanging culverts stop migrating whitebait from reaching upstream habitat. 
  • excess sediment. Too much sediment blocks the spaces between stones on the stream bed, reducing the habitat for invertebrates, such as crayfish/koura, which adult fish feed on.
  • pollution from land. Pollution reduces the water quality in streams and rivers for all aquatic life.
  • introduced and invasive plants and weeds that clog up the places where whitebait live.

Other factors

  • Introduced sports fish like trout and pest fish like gambusia compete for habitat and prey on whitebait.
  • Whitebait fishing is another pressure on whitebait populations.

What you can do to help

There are many ways we can help increase whitebait populations:

Preventing invasive species

It's important to prevent the spread of species invading New Zealand’s waterways.

To prevent the spread of freshwater pests such as didymo (an exotic alga) and freshwater gold clam (a non-native shellfish), always check that your footwear (including waders), vehicles, fishing equipment, and other items are clean and dry before entering, and when moving between, waterways. You could also choose to use your fishing gear on only one river.

More information and cleaning guidelines at Biosecurity New Zealand.

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