FACTS ABOUT THE NATIVE FRESHWATER FISHES OF NEW ZEALAND


When you think you know a bit about the plants and animals that live in New Zealand's waterways, click here to go to our Native New Zealand Freshwater Life Quiz and see how much you know!


SOME BRIEF FACTS...

  • Only about 50 species - low for a country of this size.
  • Few families (only 7) represented in our native fauna, a low diversity.
  • High degree of endemism (most species found nowhere else).
  • Only one extinction (the Southern grayling, Prototroctes oxyrhynchus) -so far...
  • More than 60% are diadromous (have a marine life stage).
  • Many probably arrived in NZ by dispersal via the sea.
  • Few native species are commercially exploited.
  • By far most are completely unknown by New Zealanders, and many are still poorly understood even by the experts.

Diadromous Lifecycle Figure

The diadromous lifecyle of Inanga.
C.L. Mitchell (1990).

SO WHY DON'T WE SEE THEM MORE?

  • Many have secretive habits e.g. some species are nocturnal.
  • They normally have cryptic colouration.
  • Few are of a great size -most of them are only around 100 mm.
  • Many of the larger and consequently more visible species are fairly rare.
  • Some have localised/ specialised distributions or habitat requirements -this factor demonstrates the frequent importance of native forest cover over their streams.
  • Their habitats may also be geographically remote.
  • Many are simply quite rare now due to historic impacts, even in areas without present significant human impact.

Some New Zealand fishes are also found in other remnants of ancient Gondwanaland (such as the inanga,Galaxias maculatus, in Australia and South America). Most, however, are endemic such as the banded kökopu (Galaxias fasciatus) which is found nowhere else in the world. Some of these are very primitive forms (e.g. the galaxiids) indicating their presence in New Zealand for a very long time, whilst other (e.g. the bullies) are of more recent evolutionary origin, with a more highly developed form and features.

New Zealand has a very small freshwater fish fauna, being approximately half that of a similar sized country. This may be explained in part through the extremely long period of time that New Zealand has been isolated from other countries by the barrier of the sea.




MAJOR FRESHWATER FISH FAMILIES

Family: Galaxiidae (Galaxiids) e.g., kökopu, inanga, whitebait.

· Gondwana distributed (Australia, South America etc.)
· Smooth, scaleless bodies
· 28 species observed with more on the way
· Very primitive body shape
· Largely nocturnal

Family: Eleotridae (Bullies) e.g. common; redfin bullies.

· Benthic (bottom-dwelling) with a reduced swimbladder (they sink)
· Some species migratory, others not
· Some can be either e.g. common bully in lakes or in coastal streams

Family: Anguillidae (Eels) e.g., longfin eels.

· There are species of eels found around the world
· Three species are known in New Zealand; one endemic (longfin eel)
· Adult longfin eels migrate to marine trenches off Tonga to spawn
· They form a major export freshwater fishery for New Zealand
· May often be very long lived (up to 70 years)
· Long-finned eels may grow to 2 metres long!


Some members of these families are listed on the following pages...


This section is not intended to be exhaustive, so for information on species not covered here we recommend NIWA's Native Freshwater Fish Atlas.

Native Freshwater Fish Atlas

Native Freshwater Fish Atlas