Koi carp found in Hauraki Plains stream
Destructive koi carp have been discovered in a Hauraki Plains stream where they have never been before, and dairy farmer Brian Pirie believes they have been deliberately released.
The introduced freshwater pest was first released in the Waikato region in the 1960s, and has since proliferated. Not only does it eat native fish and eels, when it feeds it stirs up mud, resulting in poor water quality.
Bowhunters shoot the fish, but although they kill thousands, they have failed to control them. Some bowhunters have been responsible for releasing them into rivers in the interests of furthering their sport.
Pirie said because the ones that had been seen so far were small – ‘‘about a foot long’’ – it was apparent they had been released into the Waitakaruru River only a short time ago.
‘‘The thing that concerns me is that we do all this work to protect our rivers and someone’s gone and done this, and yet we farmers take the flak for dirty rivers.
‘‘It’s really frustrating, we’ve been planting and fencing in the headwaters to keep the river clean, and these clowns come and do this downstream,’’ Pirie said.
The river is about 7 kilometres
‘‘The thing that concerns me is that we do all this work to protect our rivers and someone’s gone and done this, and yet we farmers take the flak for dirty rivers.’’ Brian Pirie, Hauraki Plains dairy farmer
long, and runs through five dairy farms.
Waikato Regional Council freshwater ecologist Dr Bruno David said it was the first report of koi carp he had heard from the river.
‘‘But they’re becoming fairly widespread throughout the Piako River system. In 2017 there was a cyclone that saw flooding in a wide area, and the carp would have access to a lot of water courses. It’s anybody’s guess as to whether they’ve been deliberately released.’’
Department of Conservation freshwater manager Keith Ikin said koi carp were a significant pest fish species and presented a major challenge for DOC and the Waikato Regional Council in the Hauraki area.
‘‘The koi carp churn up sediment and eat the eggs of native species. DOC is currently working on a range of tools to mitigate the spread of koi carp, and is collaborating with WRC on this,’’ Ikin said.
‘‘A major focus for DOC at the moment is actually determining the extent of the spread of this species, including in the Hauraki area. A key priority is containing the spread of koi carp – we need to identify locations where we can put physical barriers in place to prevent them from extending across the region.’’
It was important that fishers recognised the importance of the ‘‘check, clean, dry’’ message after fishing or boating.