More than 50 participants competed in the event, which targets koi carp – an invasive pest fish species found in the Waikato River and some of its tributaries. Competitors use modern hunting bows to target the fish which in previous years have weighed up to 11kg.
Entrants must be registered with event organiser NZ Bowhunting Society (NZBS) and be a current NZBS member.
The event is sponsored by DOC, Waikato River Authority and Bulk Allied, and the competition culminated with the weigh-in and prizegiving at Ruawaro Memorial Hall near Huntly on Sunday afternoon.
A steady stream of utes and boats pulled in to unload the hunters' catch and dump them into large plastic crates, with some hunters arriving with minutes to spare before the 4 pm deadline to maximise their hunting time.
Among those involved was Matamata's Carl Hyne – part of an intergenerational team which included his father Garry and 10-year-old son William.
Carl Hyne, a keen duck shooter, became involved in the sport as a teenager and introduced both his son and his father to bow hunting. This year's event was his thirteenth, the fifth for his father, and second for his son.
"There's a fair bit of skill involved, there's also the pest eradication part of it – and you're hanging out with a bunch of guys who like doing it too," Carl Hyne says.
"We've had a bit of banter about who shot the smallest one."
Hunters must factor in the refraction of light in water to target their prey, and NZ Bowhunters Society President Graham Warrender says a key to success is aiming just underneath the target fish.
"It doesn't work very well for me, and today will prove it!" he says. "I'd love to be a bit more accurate."
Looking for a new challenge beyond rifle hunting, he took up the sport in 1997. Because the competition is based on the weight of fish caught, Graham Warrender can participate in the event, and outside the Koi Carp Classic he's seen a hunter successfully shoot a monstrous 14 kg koi.
The Koi Carp Classic is traditionally held across a weekend in late October/early November, with spring considered the best season of the year to hunt the fish, which are entering their breeding and spawning cycle.
Graham Warrender says this year's four tons of koi is about the average total volume caught during the competition, although in ideal sunny and still conditions in 2004, more than eight tons of fish were taken from the Waikato River and its tributaries.
Kerry Bodmin, DOC's Freshwater Biosecurity Co-ordinator, says koi are an ornamental strain of carp, resembling goldfish but distinguished by two pairs of whisker-like feelers, called barbels, around the mouth.
The species is thought to have been introduced into New Zealand as part of a goldfish consignment in the 1960s, and may have found their way into Waikato waterways through illegal releases and flooding events which saw them escape from ponds on domestic properties.
Koi carp churn up the bottom of ponds, lakes and stream, causing a deterioration of water quality and subsequent habitat loss for native species.
"DOC's focus is on stopping the spread of koi carp beyond those waterways already infested," she says. "Koi carp are widespread in the Auckland and Waikato regions. Part of our management approach is the permitting of hunters like those who participate in the Koi Carp Classic.
"The more koi the competitors catch, the better it is for efforts to contain these pests."
The fish shot as part of the competition were destined to be turned into fertilizer.
