The Primary Land Users Group (PLUG) have been advocating over the last six years for a program to be established to control/eradicate Koi Carp.
Koi Carp are shown on the Department of Conservation (DOC) website, designated as an unwanted organism and a noxious species.
Koi carp cause habitat loss for plants, native fish, invertebrates and waterfowl.
They feed like a vacuum cleaner, sucking up everything and blowing out what isn’t wanted and they burrow away at the banks causing erosion7, so they contribute to poor water quality in a number of ways. Aquatic plants are dislodged in the process and are unlikely to re-establish.
Once established in an area they have a huge and significant impact on rivers and ponds. They destabilize river and pond banks and destroy habitat for native fish and waterfowl and they significantly increase water turbidity. Once introduced they quickly become the dominant fish in water bodies.
The Department of Conservation is the government agency charged with conserving New Zealand’s natural and historic heritage.
Their role is to care for the land, the waters, our native species and our heritage and two of their ten year goals are:
We have huge problems with both water quality and indigenous biodiversity from the effects of the Koi Carp, invasive pest fish species.
So in relation to the Ecosystem Health surely Koi Carp must be addressed as they have a huge effect on the rivers from the damage they do. They are one of the most rapidly multiplying invasive pests that have been released into the New Zealand environment.
Koi Carp are now common in the Waikato/Waipa waterways, but have been largely ignored with the focus for water quality improvement being almost totally on the effects from agriculture.
Recent surveys undertaken for Environment Waikato have shown that koi may now make up 80-90 per cent of the biomass of some waterways.
If koi ever reached the Rotorua or Taupo lakes, it would devastate our internationally renowned trout fisheries. People must realise that Koi Carp are a serious threat to our waterway’s biodiversity.
The Koi Carp is now rapidly becoming one of the worst invasive pests in New Zealand and as such and taking into account their geographic spread, they are a national problem and require a national solution to allow control measures to be implemented across the whole country.
To have any chance of success in addressing the desired improvements in water quality then we “MUST” put in place strategies to deal with the invasive pest fish species such as Koi Carp.
Koi Carp have now spread across the waterways of the Hauraki Plains and into the waterways above the Karapiro Hydro Dam and with their spawning rates and the lack of natural predators this is an extremely worrying spread in terms of the effects on both water quality and indigenous biodiversity.
Whether or not we have the tools to eradicate the Koi Carp is not the main issue. The most important issue is to try to control the spread and the total biomass in the waterways to protect both water quality and our indigenous biodiversity; otherwise we will not have any water quality or indigenous biodiversity to protect.
Doing nothing is not an option. We must act now!!!!
With that in mind, it is great to see that there is now a new project focused on the removal of the pest fish from waterways using traditional and new methods, and filling knowledge gaps to assist in managing koi numbers,
The new project (announced in February 2022), focused on several lakes which are part of the wider Waikato River system, sees the Department of Conservation (DOC) partner with Te Rui o Waikato, Waikato Regional Council (WRC) and Waikato River Authority (WRA). WRA has co-funded the $1,319,682.50 project through a $488,750 grant, with DOC, WRC and Te Rui o Waikato also contributing financially and with in-kind funding totalling $830,932.50 over the course of three years.
Kerry Bodmin, DOC Freshwater Biosecurity Co-ordinator, says the four-year project will start this summer, and go beyond the existing work programmes DOC and WRC have in place for koi carp management.
” Kerry Bodmin said: “Our goals for this project include reducing the rate of spread of koi by prioritizing the installation of barriers, and supporting two community-led koi removal projects.
“Partnering with mana whenua, through Te Riu o Waikato, is vital to this project and we’ll be working with them on trialling ways we can remove the koi from the waterways using long nets and disposing of the fish carcasses.” Koi will also be removed from known spawning sites, and access to those sites will be restricted to hamper reproduction of the fish.
Another important aspect of the project is biomass counts – put simply, how the koi population can be measured.
Te Rui o Waikato Chair Tawera Nikau says Waikato-Tainui has an important connection to the Waikato River and mana whenua are enthusiastic about partnering in the project to curb the pests. “Koi are a real challenge across our rohe, and this trial also presents us with some employment and economic opportunities for iwi, hapu and whanau. “We’re excited to be part of it and welcome the long-term commitment of funding to learn more about how we can control these fish and reduce them in our awa.”
WRC spokesperson Councillor Stu Husband says the organisation works collaboratively with DOC and other key stakeholders to manage and reduce the impact of pest fish – including koi – in freshwater systems at high-value biodiversity sites in the region. “We’ve contributed $250,000 for the 2022 financial year to efforts to manage koi carp – an investment we’re proud to make.” WRC also provides landowners with advice and information on the threats posed by freshwater pests.
The Waikato River Authority is one of the largest funders of environmental restoration projects in the Waikato and Waipā catchments and supports a collaborative and coordinated approach to the restoration of the catchment.
In 10 years, the Waikato River Authority has funded more than $50 million to more than 300 projects that will help restore and protect the Waikato and Waipā rivers and it is great to see that the Authority has finally seen fit to provide funding to this project which is the beginning of a long battle to eradicate Koi Carp from the catchment and protect the indigenous biodiversity.