Our waterways need to be carefully managed so native fish can access the habitats they need. These fish move within rivers and streams to and from the sea to complete their life cycles.

Many of these species, like whitebait and eels, need to move between freshwater and the sea to complete their life cycles.  Fish passage connects all the habitats that are necessary for freshwater fish to complete their life cycle. Disconnections between the water upstream and downstream of a structure can stop or slow down fish passage. This can be caused by culverts with a significant drop at the downstream end,  extremely long structures like pipes, fast water flow through a structure and weirs that are too high for fish to navigate. As a result fish numbers can be reduced, or they may be completely lost from a stream. Some fish species are more affected by instream structures than others. For example, inanga are weak swimmers, whereas kōaro whitebait and baby eels can climb wet surfaces very effectively.