New Zealand's native freshwater fish are a significant part of our country's biodiversity, each with its own fascinating life history. Their origins and relationships are part of our country's evolutionary history.
Most of these fish such as tuna, kōkopu and kanakana, are important traditional foods for Māori and are regarded as taonga. Many of the same species are more commonly known to New Zealanders as 'eels' or 'whitebait' and form important commercial fisheries. In fact, New Zealand has more than 40 native fish species.
Cawthron scientists are able to identify the species and variety of habitats that these fish occupy in our rivers and streams.
Cawthron's services in this area include:
- A variety of survey techniques including electric fishing, trapping, spot-lighting and sonar detection (DIDSON)
- Habitat measurement and assessment
- Predictive modelling
- Fish passage solutions.
Fish passage solutions
Some New Zealand freshwater fish begin their life cycle in the sea. For others, the sea is where they complete their life cycle. This relationship with the sea can result in long and difficult journeys up and down rivers as these fish seek their various habitat needs. If barriers are placed in the way of migrating fish, their choice of habitat becomes limited and this in turn causes a decline in their numbers.
Cawthron scientists can advise on the fish species present in any waterway, the habitat requirements of the fish, and solutions to allow fish passage where barriers are created by weirs, fords, bridge aprons, culverts and dams.
Cawthron provides additional advice on:
- Synoptic surveys to establish fish species presence and distribution
- Habitat assessments to establish likely natural migratory pathways
- Fish pass design, existing structure retrofitting and habitat improvements to enhance fish passage.