Freshwater quality

Understanding and predicting the sources of contaminants, developing technologies to clean up the sources, and understanding the consequences of water quality degradation for aquatic ecosystems and human use of waterways.

NIWA has developed a model to assess the potential weed risk of aquatic plants.

NIWA is involved in research and consultation' aimed at improving the health of our freshwater systems.

Small native fish eat a range of benthic invertebrates in streams. The larvae of mayflies and caddisflies are the most important food species, with chironomids being important for juvenile fish and in streams where all other prey are scarce.

A problem with recruitment is usually indicated by the absence, or very low density, of fish where they would normally be present.

Fish species thrive in a variety of different habitats.

Low recruitment could also be caused by widespread depletion of stocks