Feature Fish

 Longfin eel 
(Anguilla dieffenbachii: Family Anguillidae)

The longfin eel is endemic to New Zealand and is classed as Declining by the Department of Conservation. It is obligatory diadromous. Longfin eels are found in a variety of habitats in Wairarapa Moana but prefer clean, cold-water environments such as forested rivers and streams. Longfin eels are the largest freshwater eel species in the world. Individuals over 20 kg in weight and almost 2 m long have been recorded. They are long-lived (some females have been aged at over 100 years old). They will breed just once at the end of their lives. To do so adult eels swim all the way out into the Pacific Ocean near Tonga.

 Shortfin eel
(Anguilla australis: Family Anguillidae)

The shortfin eel is native to New Zealand, but is also found in eastern Australia and some Pacific Islands.  It is obligatory diadromous and is found in a wide variety of habitats in Wairarapa Moana. It is predominantly in lowland areas being found in lakes, wetlands, rivers and streams. Shortfin eel commonly reach 60 cm in length.

 Common bully
(Gobiomorphus cotidianus: Family Gobiidae)

The common bully is endemic to New Zealand. It forms both migratory and non-migratory populations. Common bullies occur in a wide variety of habitats in Wairarapa Moana and can be found in rivers, streams, lakes and wetlands.  They can be readily observed hopping along the lake bottom in the shallow margins of Lake Wairarapa. The common bully commonly grows to 10 cm in length.

 Inanga
(Galaxias maculatus: Family Galaxiidae)

The inanga is native to New Zealand and is also found in South Australia and South America. It is classed as “Declining” by the Department of Conservation.  Inanga are the most common of the five species that make up the ‘whitebait run’. They commonly grow to around 10 cm in length.

Inanga are diadromous (although can form non-migratory populations). They typically require coastal wetland vegetation for spawning - which these days has often been degraded. Inanga are commonly found in a range of habitats throughout Wairarapa Moana, although they are more common in lowland areas. Adults can sometimes be observed loosely schooling in the lower reaches or larger rivers and lakes (where visibility allows).

 Giant kōkopu
(Galaxias argenteus: Family Galaxiidae)

The giant kōkopu is endemic to New Zealand. It is classed as Declining by the Department of Conservation.  This fish can grow up to half a metre in length and weigh over 2 kilograms. 

The giant kōkopu is diadromous and juveniles are found in ‘whitebait’ catches during their upstream migration.  Giant kōkopu do not usually penetrate very far inland and tend to inhabit slow flowing streams, lakes and wetlands.  The degradation of Wairarapa Moana has had a particularly strong impact on this species due to the magnitude of wetland habitat loss. 

A few records exist for this species, scattered throughout Wairarapa Moana and its tributaries and associated wetlands.  These days it is rarely encountered within Wairarapa Moana.

 Brown mudfish
(Neochanna apoda: Family Galaxiidae)

The brown mudfish is endemic to New Zealand. It is classed as Declining by the Department of Conservation. Brown mudfish can grow to up to 17 cm, but are more often around 10 cm. This species is non-migratory and completes its entire lifecycle in freshwater. 

Brown mudfish are true wetland specialists and are rarely found elsewhere. Ideal brown mudfish wetland has dense vegetation and dries up during summer months. Mudfish can survive these dry periods by sheltering under damp vegetation and woody debris. As long as they remain damp they can survive dry periods of several months (this process is called aestivation).

Brown mudfish can still be found in a number of wetlands throughout Wairarapa Moana, but populations are scattered and fragmented. The loss of over 97% of wetlands in the Wellington region has had a significant impact on the distribution and abundance of this species.

 Common smelt
(Retropinna retropinna: Family Osmeriidae)

The common smelt is native to New Zealand and is also found in south eastern Australia.  This fish commonly grows to around 9 cm. It is diadromous, although can form non-migratory populations.  Common smelt are found in estuaries, lakes and rivers and occur throughout Wairarapa Moana. It can sometimes be observed loosely schooling through the water column. Strangely, common smelt have a strong cucumber-like smell. 

 Black flounder
(Rhombosolea retiaria: Family Pleuronectidae)

The black flounder is endemic to New Zealand.  This fish usually grows to around 20 – 25 cm long and is diadromous.  Black flounder inhabit coastal lakes and the slow-flowing areas of rivers. In the Ruamahanga River they have been observed as far inland as Masterton.  This species was previously so numerous in Lake Wairarapa that it supported a number of small commercial fisheries, however, these days it is far less common.

 Yelloweye mullet
(Aldrichetta fosteri:Family Mugilidae)

The yelloweye mullet is native to New Zealand, but is also found in Australia. It often grows to around 20 cm.  The yelloweye mullet is predominantly a marine species, but is also commonly found in harbours and estuarine areas and is therefore classed as a ‘marine wanderer’.  This species is frequently observed in Lake Ōnoke and around the southern end of Lake Wairarapa.