New Zealand fish passage guidelines
Many of New Zealand’s most widespread fish species (e.g., whitebait and eels) undertake significant migrations as part of their life-cycle. The purpose of these migrations is to access the range of habitats necessary to support different life-stages, e.g. reproduction and rearing, and ecological functions, for example feeding or finding refuge.
Instream infrastructure, such as culverts, weirs and dams, can delay or prevent fish movements when adequate provision for fish passage is not provided in their design, installation and maintenance. The consequence is a reduction in the distribution and abundance of some of our most iconic and valued freshwater species.
The New Zealand Fish Passage Guidelines sets out recommended practice for the design of instream infrastructure to provide for fish passage. The intent of these guidelines, developed by NIWA and the Department of Conservation in partnership with the New Zealand Fish Passage Advisory Group, is to set the foundation for improved fish passage management in New Zealand.
These guidelines have been developed to assist infrastructure designers and managers, waterway managers, environmental officers, iwi and local communities with understanding and promoting better management of fish passage requirements in New Zealand. The guidelines set out best-practice approaches and minimum design standards for providing fish passage at instream structures based on current knowledge. The general principles of good fish passage design set out in these guidelines should provide a basis for developing suitable infrastructure designs in the majority of situations most regularly encountered in New Zealand.
The guidelines are based on the principle that good fish passage design achieves the following general objectives:
- Efficient and safe upstream and downstream passage of all aquatic organisms and life stages resident in a waterway with minimal delay or injury.
- A diversity of physical and hydraulic conditions are provided leading to a high diversity of passage opportunities.
- The structure provides no greater impediment to fish movements than adjacent stream reaches.
- Continuity of geomorphic processes such as the movement of sediment and debris.
- Structures have minimal maintenance requirements and are durable.
For further resources on fish passage management in New Zealand please visit the Department of Conservation fish passage webpages.