Spot the difference: Grass carp have made a huge impact on water quality at Maygrove Lake in Orewa. The water looks pristine at the northern end (left) which has grass carp in it. By contrast, the southern end, above, which does not currently contain the fish, is chocking up with weeds. Gray Jamieson says he has removed around 70 of his grass carp from artificial lakes in Gulf Harbour. This was one of the biggest, weighing in at around 20kg, taken from the Oval Lake on May 4. The Gulf Harbour Radio Yacht Club would have to close if Regency Lake fills with weed. The club has around 30 members and has been sailing its yachts on the lake since 1995.
A dispute over payment for grass carp could have a big impact on the appearance and use of the artificial waterways around Gulf Harbour, including the largest one, Regency Lake. However, Gulf Harbour Country Club has said that it will ensure that won’t happen.
The grass carp are herbivores and eat weeds that grow in fresh water. Owner of the carp, NZ Waterways Restoration, is in the process of removing them from the waterways around Gulf Harbour because of a dispute with the organisation responsible for the lakes, Gulf Harbour Country Club.
NZ Waterways Restoration’s director, Gray Jamieson, says the waterways will become a lot harder and more expensive to maintain and could become smelly and clogged with weeds once the carp go.
However, the Country Club, which uses the artificial lakes to irrigate its golf course, has given an undertaking that the water quality will be maintained.
Its director of golf, Fraser Bond, says the club will make sure of this not only because it needs the water to keep the course looking pristine but because it owes it to the community. He says options being considered include “putting more carp in or pump systems” – the latter would, he says, come at a massive cost.
“The lake is something that we care hugely about because it is important for all our members and the wider community,” Mr Bond says. “We will make a commitment that the water will stay clear.”
Earlier this month, as Mr Jamieson pulled out 44 huge carp from the Oval Lake (behind the sports field opposite Wentworth College), he said he has left removal of his fish from the lakes on the golf course itself until last. “I wanted to give the club as much time as possible,” he says. “They have given me a trespass notice so I’m anticipating trouble when I go to get those fish.”
The use of grass carp in NZ is controversial, as they are an introduced species. However, the climate means they are unable to breed here.