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Fish Passage Assessment Tool

Many of New Zealand’s most widespread fish species (e.g. whitebait and eels) undertake significant migrations as part of their life-cycle. However, instream infrastructure, such as culverts, weirs and dams, can delay or prevent fish movements and stop them from accessing critical habitats.

The Problem

Instream structures can reduce the abundance and distribution of valued freshwater species when adequate provision for fish passage is not provided in their design, installation and maintenance. To understand the size of this problem and develop effective solutions, we need to know where these structures are on our rivers and how much they restrict fish movements.

The Approach

The Fish Passage Assessment Tool has been developed to provide an easy to use, practical tool for recording instream structures and assessing their likely impact on fish movements and river connectivity.

Data is collected using the Fish Passage Assessment Survey available in the NIWA Citizen Science app. This provides a standardized way of recording data on the characteristics of instream structures and assessing accessibility for fish. The information collected using the app is automatically uploaded to a national fish passage database.

All data that have been collected using the Fish Passage Assessment Survey can be viewed and downloaded from the Fish Passage Assessment Tool webpage ( Each structure is assigned a fish passage risk class and an ecological prioritization score.

The information collected using the Fish Passage Assessment Tool will help us to understand and visualize the connectivity of New Zealand’s rivers and track progress of work intended to restore fish passage.


Download the Fish Passage Assessment Survey app User Guide

The Fish Passage Assessment Survey app is available for iOS and Android operating systems and can be downloaded from:

Other resources

The New Zealand Fish Passage Guidelines set out recommended standards for the design and restoration of instream infrastructure to provide for fish passage.

For further resources on fish passage management in New Zealand please visit the Department of Conservation fish passage webpages.


Development of this tool was funded by MBIE through Envirolink Tools contract C01X1609 and supported with funds from the European Commission through the Marie Sklodowska-Curie action, “Knowledge Exchange for Efficient Passage of Fish in the Southern Hemisphere” (RISE-2015-690857-KEEPFISH).


Research subject: BiodiversityFishRivers