| Distribution is localized and non breeding, recorded from the North and South Is. Range is expanding (Ref. 52336). Reintroduced in 1969 and 1971. The fishes were introduced to assess their value in controlling weed growth in nutrient enriched waters. After 15 years of research it was concluded that the fishes were environmentally safe, damage to native and introduced fisheries would be minimal, the likelihood of breeding was low, and harmful effect of weed removal by fish would be much less than by herbicide or mechanical means. Stocks have been maintained by inducing breeding in captivity using hormone treatment, stripping and artificially fertilizing eggs, and rearing larvae in the hatchery. General use of the fish in the wild in New Zealand has utilized sterile triploid stocks, this likely to change but (in 1994) awaits a decision by the Minster of Conservation. Also Ref. 1993, 11115 and 74657.
Ref:
Mitchell, C., 1977
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