Lake Huro is a coastal dune lake on Chatham Island, New Zealand, southwest of Te Whanga Lagoon and close to the settlement of Waitangi. Hosting many waterfowl and a population of New Zealand smelt, the lake has very poor water quality, with green and cloudy water, and poses a potential toxic hazard due to its outflow through MangapÃÂ Creek to the Nairn River and Waitangi.
Lake Huro is a coastal dune lake on Chatham Island, New Zealand, located on a strip of land between the Te Whanga Lagoon and the settlement of Waitangi. It covers an area of around , but with a maximum depth of only .
The lake's sediment mostly consists of sand, with a crust of peat along its shores. The water is green and turbid, stained by the peat. The water visibility was measured in 2004 as just , although the growth of Myriophyllum (water milfoil) plants in the lake may have led to some increases. MangapÃÂ Creek drains the lake, running through an area of farmland into the Nairn River (also known as Mangatukurewa Creek) south of Waitangi. The surrounding land is mainly used for livestock grazing, with animals given direct access to the lake. It has similar water characteristics to other coastal dune lakes on Chatham, especially the nearby Tennants Lake and Lake Rangitai.
The lake's water degraded during the early 2020s to hypertrophic, the lowest possible water quality level according to the New Zealand trophic level index. It has moderate levels of phosphorus and ammoniacal nitrogen, but severely high amounts of nitrogen and algae. In a 2022 survey, Huro was the only one of the island's lakes where Chlorophyll a levels were not found to have increased. The lake's poor water quality poses a risk to nearby settlements, as MangapÃÂ Creek and Mangatukurewa Creek drain into a well populated waterfront area in Waitangi. Potential blooms of toxic cyanobacteria could endanger nearby livestock, wildlife, shellfish, and local residents.
Lake Huro hosts a significant population of waterfowl, such as the introduced black swans. It hosts a large population of New Zealand smelt, alongside small numbers of redfin bullies (a species of goby). In 1949, smelt from the lake (alongside samples from nearby Tennants Lake and Lake Marakapia) were described as a separate species from New Zealand smelt, R. chathamensis; this was later synonymised with Retropinna retropinna, New Zealand smelt. Lake Huro seems to have a genetically distinct population of smelt compared to Lake Marakpia and Tennants Lake. A species of the algae Lamprothamnium grows in the lake.