New Zealand native Redfin Bully
New Zealand has a sparse but unique freshwater fish fauna. There are about 35 species, many of which are only found in this country (endemic). The well-known ‘whitebait’ are the juveniles of five native species from the Galaxiid family. There are also eels, bullies, torrent fish, lamprey and several marine species that wander into rivers (such as yellow eye mullet, stargazers, tripplefins and flounders). Many of our native fish species are diadromous, which means that they spend part of their lifecycle in the sea, and part in freshwater streams. White bait species, such as inanga, lay their eggs amongst grass along the margins in the upper estuaries. The newly hatched larvae swim out to sea where they feed and grow. These ‘whitebait’ swim back up the streams and grow into adults. It is important for the some fish species (including longfinned eels and banded kokopu) to be able to migrate all the way up a stream, with out any barriers (like dams, pipes and pollution) so that they can breed and complete their life cycle. During the daytime, many native fish species hide under banks or beneath rocks on the streambed, or amongst woody debris.
In addition to our native fauna, several other species of fish have been introduced to New Zealand, including all the species of trout and salmon, as well as fish like perch, catfish and goldfish. Some introduced species are considered to be nuisance species because they may have negative impacts on the environment or the native fauna. Among the real pests in Auckland are Koi Carp and Gambusia (mosquito fish). It is important that you do not release these fish into any streams or lakes.
For further information regarding freshwater fish see:
http://www.nzfreshwater.org/index_main.html – Freshwater Fish Society
http://www.niwa.cri.nz/rc/freshwater/fishatlas/ - NIWA fish Atlas
http://www.doc.govt.nz/Conservation/002~Animal-Pests/Pest-Fish-(Freshwater)/index.asp – pest fish
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