The southern Wairarapa has two major lakes. About 18 km long and 6 km wide, Lake Wairarapa is shallow – mostly less than 2.5 metres deep. Covering 7,800 hectares, it is the biggest wetland in the lower North Island, and has long been an important Māori eel fishery. Lake Wairarapa drains into tidal 650-hectare Lake Ōnoke, to the south. Lake Ōnoke is separated from the open sea of Palliser Bay by a 3-km gravel spit.
Originally, Lake Ōnoke’s mouth at the eastern end of the spit opened and closed in response to weather and other conditions. When closed, the lakes’ levels rose, sometimes causing flooding.
Europeans farming the land wanted to open the spit to reduce flooding. Māori resisted, believing it would threaten their fisheries.
Battle of the spit
In 1886 Pākehā formed the Ruamahanga River Drainage Board to control Lake Ōnoke. In May 1892, they attempted to open the spit. This was resisted by the Ngāti Kahungunu leader Piripi Te Maari-o-te-rangi and his followers. As digging began, they grabbed the workers’ shovels, halting the work. Pākehā onlookers linked hands, forming a chain around the diggers. Several Māori women dived under the link and started filling the trench. Unable to complete the task, the board decided to prosecute for obstruction. Happy to get a court hearing, the protesters performed a celebratory haka (war dance). They then allowed work to continue.
The Supreme Court found in favour of the board, but in 1895 Piripi Te Maari-o-te-rangi petitioned Parliament. An inquiry found he had been wronged and recommended his grievances be redressed.
A meal of eels
When the Lake Ōnoke spit was closed off from the sea, often in late summer, Māori caught eels by digging a trench in the sand between the lake and sea. As water started to rush through, the eels followed, believing it was a passage to the sea. The opening to the trench was then filled in, trapping the eels, which were dried or smoked and used for trade.
Gifting the lakes
In 1896, after Te Maari-o-te-Rangi’s death, Hāmuera Tamahau Mahupuku gifted the lakes to the Crown. This ensured the mana (spiritual power) of the lakes remained with Wairarapa Māori. In exchange, the Crown paid £2000 and promised to set aside land for Māori. However, only one reserve was set aside. This was part of the Pouakani Block in faraway southern Waikato, comprising swamp and bush-covered hills, with infertile pumice soils.
The government allowed areas of the lake edge to be drained and converted to pasture. After a severe flood in 1947 the lower Ruamāhanga River was diverted to flow directly into Lake Ōnoke. A 1980s plan to reclaim more of the lake bed for farming was stopped because of environmental concerns, and in 1989 a conservation order was placed over the lake to protect its wildlife. Two years later local interest groups formed the Lake Wairarapa Co-ordinating Committee. Issues include reducing runoff from pasture, managing hunting and gathering rights, and protecting the habitats of rare native species.
Plants and animals
Lakes Wairarapa and Ōnoke are among the North Island’s most important wetlands.
The lake edge supports over 40 species of native aquatic turf plant, such as swamp grass, raupō and flax. At the edge of wetlands there are large areas of mingimingi, kānuka and mānuka. There are also stands of kahikatea and cabbage trees. Crack willow, hawthorn and alder are the main exotic species.
The eastern side of the lake is the most significant area for wildlife, providing a habitat for the bar-tailed godwit, golden plover, banded dotterel, Japanese snipe and Caspian tern. The lake supports a range of waterfowl, including grey and mallard ducks, grey teal, and paradise shelduck. Three species of shag and the pied stilt also live in the wetlands.
Two nationally threatened fish species, the brown mudfish and giant kōkopu, live in the wetlands. Eel and black flounder migrate from the sea from midsummer to autumn. Exotic fish – brown trout, perch and (noxious) rudd – are established, but their impact on native species is not known.