Proposed Waikato Regional Plan Change
1 – Waikato and Waipa River Catchments
Koi Carp Issues
The Healthy Rivers: Plan for Change/Wai Ora: He Rautaki Whakapaipai project Vision and Strategy required the development of a plan for the rivers to be swimmable and safe for food collection.
The change to the Operative Waikato Regional Plan (WRP) is designed to restore and protect water quality in the Waikato and Waipa Rivers by managing nitrogen, phosphorus, sediment and microbial pathogen levels in the rivers.
The Vision and Strategy states that the Waikato and Waipa Rivers are degraded and require restoration and protection and that one method for this will be provided by ongoing management of diffuse and point source discharges of nitrogen, phosphorus, sediment and microbial pathogens.
Yet arguably the largest contributor to sediment loading in the rivers is ignored in this plan change – KOI CARP!
The plan change document includes the table shown below:
Ecosystem health
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The Waikato and Waipa catchments support resilient freshwater ecosystems and healthy freshwater populations of indigenous plants and animals.
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· Clean fresh water restores and protects aquatic native vegetation to provide habitat and food for native aquatic species and for human activities or needs, including swimming and drinking. · Clean fresh water restores and protects macroinvertebrate communities for their intrinsic value and as a food source for native fish, native birds and introduced game species. · Clean fresh water supports native freshwater fish species. · Wetlands and floodplains provide water purification, refuge, feeding and breeding habitat for aquatic species, habitat for water fowl and other ecosystem services such as flood attenuation. · Fresh water contributes to unique habitats including peat lakes, shallow riverine lakes and karst formations which all support unique biodiversity. · Rivers and adjacent riparian margins have value as ecological corridors. |
Koi carp contribute to poor water quality and are a serious problem in both Australia and New Zealand.
What damage do they do?
When they feed they stir up the bottom of ponds, lakes and rivers, muddying the water and destroying native plant and fish habitat. Koi carp are opportunistic omnivores, which means they eat a wide range of food, including insects, fish eggs, juvenile fish of other species and a diverse range of plants and other organic matter.
They feed like a vacuum cleaner, sucking up everything and blowing out what isn’t wanted. Aquatic plants are dislodged in the process and are unlikely to re-establish. Koi carp cause habitat loss for plants, native fish, invertebrates and waterfowl.
Koi Carp can produce approximately 14 times their own body weight of sediment each day through this feeding method.
Where are they found?
Koi carp prefer still waters in lakes, or backwaters in rivers. They are highly tolerant of poor water quality and contribute to water quality decline.
Koi carp are widespread in Auckland and Waikato.
Legal designation
Impact of pest fish
Many people are unaware of the damage done to our waterways by pest fish. Unfortunately some types of introduced fish have spread into the wild, become pests and are threatening New Zealand’s freshwater species and environments by:
So in relation to the Ecosystem Health as set out in the plan change document, surely Koi Carp must be addressed as they have a huge effect on the rivers from the damage they do.
But of course any control methods must be funded from the ratepayer’s funds as the ownership and spread of the KOI Carp problem cannot be, attributed to/passed on to, any particular industry group.
Andy Loader
Co-Chairman P.L.U.G.