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Providing fish passage

Providing fish passage

Updated 21 August 2015 9:27am

Shortjaw kokopu image

Native freshwater fish in the Wellington region

The Wellington region is home to at least 20 species of native fish, which makes our region one of the most diverse for freshwater fish in New Zealand. Many of these fish need to migrate between freshwater rivers and streams and the sea, as part of their natural life-cycle.

This type of life-cycle (known as diadromy) is common amongst New Zealand freshwater fish, making them unusual compared with fish from other countries. Fish species that undertake this type of migration include some of New Zealand’s most popular recreational fishing species such as the five native species that are collectively known as whitebait, and longfin and shortfin eels. As a result, the survival of many of our native freshwater fish species depends on being able to migrate. For more information see freshwater fish.

Barriers to fish passage

Migrations of native fish can be blocked by barriers in rivers and streams. Some of these barriers are natural, like waterfalls and large rapids. However, artificial structures such as flood gates, weirs, and dams can prevent native fish from completing the migration phase of their life-cycle needed for successful reproduction. Even small artificial structures such as culverts can act as barriers to fish. These barriers prevent fish from reaching upstream habitat, affecting their abundance and distribution.

Artificial barriers to fish movement have contributed to the decline of our native freshwater fish populations, and the quality of our freshwater ecosystems.

Landowner responsibilities

All landowners have a responsibility to allow for fish passage when managing or creating structures in watercourses under the Fisheries Regulations 1983. Greater Wellington Regional Council’s Fish Passage Programme contributes to this responsibility by:

  • providing advice on best-practice methods for maintaining and restoring fish passage
  • identifying and removing fish passage barriers on lands managed by GWRC
  • providing information and resources on fish passage
How you can help

Torrent fish imageIf you are planning to carry out works in a watercourse on your property or development site you should consider how this might affect fish passage.  For more information on maintaining or restoring fish passage see the links below:

GWRC can also advise you on how to ensure that any new structures allow for fish passage and whether resource consents may be required (see related links).

For more information, you can contact GWRC's Biodiversity department by emailing