Koi Carp and other Invasive Species

Introduced Pest Species

There are a number of pest species present in the lower Waikato catchment. A document detailing them as well as outlining methods to prevent their spread can be found here.

Koi Carp

Nobody knows exactly when Koi Carp were first introduced into the Waikato environment, but best estimates put it at sometime in the late 1970′s. Evidence suggests that Koi Carp – Cyprinus carpio – were established in some New Zealand waterways through escapes and illegal releases by some misguided individuals. By 1983 it was noted that Koi Carp were well established in the lower Waikato and were breeding.

A single large female Koi can produce up to 1 million eggs and as a prolific breeder the Koi has been classified in New Zealand as a noxious pest fish. Koi carp dig for food in the mud and can damage waterways by undermining the banks which causes the banks to erode and then collapse.

Koi Carp Bowfishing History

The New Zealand Bowhunters Society members have been hunting koi carp in the many miles of waterways and lakes that connect into the lower Waikato River system since 1988.

In those early years of bowfishing it was illegal to catch and have a koi carp in your possession, so the Department of Conservation (DOC) gave our members special dispensation to take koi.

The NZ Bowhunters Society currently has two annual access permits to hunt koi carp in the Waikato region and these are available to all financial members.

These permits are from the Department of Conservation and Fish & Game NZ. The Fish and Game permit excludes the shooting season but the DOC permit covers the full year. They are only available to NZBS members so carry your membership card with you.

See the individual permits for full terms and conditions as well as a list of all the wetland reserves covered by each permit. You might find some new hunting areas there!

Finding Koi Carp

September through to Christmas have proved to be the best time to find carp, this is the time when they spawn and big numbers and large sized fish can be found, Eggs can comprise up to 2 kg’s of akoi1 female Koi’s weight. Flooding at anytime of the year can see carp out feeding on riverflats and paddocks, often with half their backs out of the water. It is however recognized that the warmer summer months see the Koi much more active and thus easier to find. At other times carp seem to prefer the shelter of trees and weed beds whether foraging or just lying still under their protection. Carp seem to prefer the waterway margins and rarely travel on the surface when in open water, so if you find a point of land or weed bed that juts out then you may find carp regularly in these areas. Carp need to be stalked and will not tolerate a sloppy approach, they are wary of any visible movement and the thump of a heavy footfall or stick broken underfoot while closing in will send them into deep water. While wading you must again be cautious, Koi are very sensitive to water movement and can easily pick up the ripples of moving water from an approaching hunter.

River Levels

Koi carp hunting is always better when river and lake levels are rising. This provides new feeding areas for the koi which come into the shallows to feed, often with their backs out of the water, making them easier to see and shoot. Fortunately, there is a very easy way to check on these levels so you can plan the best time to hunt.

The Waikato Regional Council monitors the water level at 61 different sites from Lake Taupo to Port Waikato and the results are displayed on-line and updated every 15 minutes. Go to the website http://www.waikatoregion.govt.nz/ and select River Levels. That takes you to a map showing all the monitoring sites.

You may need to zoom in to find the one nearest to your hunting area, then click on that. You will now see an up-to-date chart showing the river or lake levels for the last few days with the option to select a wider date range (up to a year). This clearly shows the rise and fall of water levels that is so crucial to the feeding habits of koi carp.

Equipment – Bows

Any bow type will do the job, compound, recurve or longbow. The draw weight shouldn’t be too heavy, anything over 35 pounds will do but somewhere between 50 and 60 pounds would be considered best. Hundreds of shots can be taken while shooting at the World Koi Carp Classic so the lighter end of the suggested draw weight would be an advantage and a consideration when deciding on your bow. A heavier draw weight  will help where bigger Koi are concerned. Large Koi have large strong scales protecting their bodies and a shot on a large approaching fish can result in the arrow punching the scale out and not penetrating the fish at all. Your fishing bow needs to be a second hand or cheap purchase, remember it will be in and around water when out in the field ( your fishing bow will conceivably be used on saltwater excursions too) so don’t buy anything  to expensive. Always wash down and clean your equipment after use and it will look after you when out hunting. The arrow rest needs to be sturdy, most dealers will supply a specific bowfishing arrow rest or you can make one at home, but it must be strong to take the heavy fiberglass arrows you will be shooting off it.


The fiberglass fish arrow is the obvious chose, they have the weight needed and will take the punishment of fish after fish. Always have a few spare arrows with you while out in the field. The chose of fish point is personal preference but a style with reversible barb is a definite advantage. If the shooting is intense you need to kill and remove the Koi from you arrow as quickly as possible – the reversable barb allows you to do this. Although some fish arrows come with rubber fletched, these are not required and most if not all successful Koi hunters use arrows with no fletches at all, shots are almost always at close range and even at extreme range (anything  20 feet or more ) there is no accuracy loss from not having fletches. All you need to do is test shoot your setup to make sure the nock point is correctly set on the string. The AMS slide system is another part of the fish arrow that is simple but has made a big improvement to the overall fish arrow setup, well worth looking into.


Fishing reels come in a number of shapes and sizes & can range from NZ$35.00 to over NZ$250.00. The basic wind-on reel will do but requires the time to re-wind the line back on after each shot, which can cost time. Closed-face reels like the Zebco are faster to use and rewind but you have to remember to click the button on the back of the reel to release the arrow for every shot, it’s no fun at all if you forget to click the release button in the heat of the moment and then release an arrow that doesn’t want to leave your bow! By far the most popular reel used by bowhunters today is the ‘Retriever’ which has been specifically designed for bowfishing. This reel allows the shooter to quickly retrieve an arrow, re-nock it to the string and shoot without any other actions. These reels can be loaded with very strong fishing line with hundreds of pounds of breaking strain which is another plus as it helps when pulling an arrow out of thick weed or tree roots.

Fish baton

You will need to pacify your Koi when you get him in, as quickly as possible. There are several ways of achieving this. Some fisherman like the solid baton – one good hit hard on the head and the job is done. An addition is a bolt protruding through the baton about an inch, with one hit this is aimed at penetrating the skull above the eyes and works extremely well.

Boat or no Boat?

Koi can be hunted with or without a boat, it is however an advantage to have a boat as this means you can travel on the waterways to get to your chosen area. Once there you can shoot from the boat or walk the banks. If you chose to shoot from the boat, as already explained you will need to be very quiet, any noise like a paddle bumped even lightly against the side of an aluminum boat will send the fish into hiding.

Other Misc Items to think about!

For the World Koi Carp Classic, will transport all your fish back to the weigh in but when you are just out for the day you need to dispose of any of your Koi that you don’t want to take home. It is very important to take a responsible attitude toward this part of the hunt. You will need to take a spade with you so you can bury any Koi you have killed. Simply dumping Koi in the nearest blackberry bush isn’t good enough, the reputation of all other bowhunters will be judged by your actions or lack of, so act responsibly and properly dispose of your kills, it’s part of your DOC permit conditions.

Already mentioned was the need for a few spare arrows, but remember to also take along a few basic tools, whether it’s for the outboard motor or a repair of your bow, fishing reel or arrow, these will be handy. Murphy’s law – If you don’t have them, you will need them!

A large strong fish bin or 2 is a good investment, far better than just dropping fish into the bottom of your boat, they will make cleaning up much easier at the end of the day.

Don’t forget a  small set of weighing scales for the big one.

Even though you will be shooting your Koi very close to the surface of the water it is still a distinct advantage to have polarizing sun glasses.

And a pair of old sneakers is a must, you will be slopping about in mud, water and undergrowth a lot so don’t take your good ones or they won’t be good for long.