Progressive Control Pest
Koi Carp are an ornamental strain of carp that were accidentally introduced into New Zealand in the 1960s. They resemble large goldfish, reaching 75 centimetres in length and up to 10 kilograms. They can be distinguished by the presence of two barbels (feelers) at each corner of their mouths. They are highly variable in colour and often have irregular blotches of black, red, orange or white. They were first recorded in the Tasman-Nelson region in 2002 and an active campaign has been conducted against them, along with other pest fish, in the Tasman-Nelson region by the Department of Conservation.
Reasons for the Strategy
Koi Carp are omnivorous, feeding on insects, spawn, juvenile fish, plants and other organic material. They operate like vacuum cleaners, sucking up mud off the bottom and then discharging the unwanted material. They dislodge plants and other bottom-dwellers, destroying aquatic habitat and muddying waterways. They are classified as a “noxious fish” under the Freshwater Fisheries Regulations 1982 and an“unwanted organism” under the Biosecurity Act 1993. They grow rapidly and from two years of age, the females can produce several hundred thousand eggs. They are tolerant of a wide range of temperatures, low oxygen levels, high turbidity and the presence of pollutants.
Koi Carp is assessed at “2” on the infestation curve. It has been recorded in a small number of ponds on privately owned land in Tasman District. The low incidence of Koi Carp in the Tasman-Nelson region, extensive areas of suitable habitat, and the potential for it to cause significant adverse effects, mean the benefits of progressive control far outweigh the costs.
To reduce the distribution and density of Koi Carp in the Tasman-Nelson region during the term of the Strategy.
The alternative option of “do nothing” or relying on voluntary control will not achieve the objective of reducing the distribution and density of Koi Carp, and will result in significant additional costs to the community with respect to lost natural values and the increased cost of control in the future.
Strategy Rule for Koi Carp
The occupier shall report any suspected sightings of Koi Carp and allow access to the Management Agency, the Department of Conservation or their agents, to destroy all adult and juvenile forms of Koi Carp in water bodies on land that they occupy. A breach of Strategy Rule 5.6.5 is an offence under Section 154(r) of the Biosecurity Act 1993.
Biosecurity Act Requirement
No person shall knowingly sell, propagate, breed, release, or commercially display Koi Carp, under Sections 52 and 53 of the Act.