The discovery of what is thought to be the largest Koi carp every caught in Northland is the cause of serious concern
for Department of Conservation staff.
The enormous fish was caught by freshwater fish expert Mike McGlynn in Kerikeri while undertaking a exotic fish survey.
Mr McGlynn said the find was a major worry for conservationists.
The fish was 752 mm in length and weighed 9kg. More commonly, they grow to 600 mm in length and weigh 5kg but are likely
to be mature at half this size
“The only thing that kept this from being an environmental disaster was that there was only one fish and no opportunity
for it breed” explained Mike McGlynn.
The fish was released five years ago into a private garden pond - a pond which has overflow channels into the Kerikeri
River system. Koi carp breed prolifically with a single fish laying between 800,000 to 1 million eggs.
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. The affect on the water quality is dramatic as they disturb the
bottom of streams and ponds as they grub through bottom sediments and uproot plants, significantly increasing water
turbidity.
The koi is an opportunistic feeder, eating insects, juvenile fish of other species, a diverse range of plants and
organic matter. Once introduced they can quickly become the dominant fish in water bodies.
The Department is now working to determine how widespread koi carp are in Northland and is striving to ensure that koi
carp are eradicated from Northland before they spread out of control.
The fish could have a devastating effect on our natural waterways and DoC would like to work with landowners to get rid
of this threat. Anyone who may be aware of the possible location of koi carp are encouraged to contact their nearest
Department of Conservation office with details.
ENDS