Grass carp are free to graze on weeds throughout Maygrove Lake in Orewa after a net dividing the lake in two was removed on Sunday, November 19.
The fish were introduced to the lake in 2015. At that time, a net was suspended from a bridge to prevent them from entering the southern side, where they could potentially be washed over the weir and into the estuary.
The use of grass carp for weed control has been controversial as they are an introduced species. However, Gray Jamieson of NZ Waterways Restoration, who supplies the carp, says they cannot breed in NZ and are ideal for weed control in enclosed sites such as Maygrove Lake.
Since they were introduced, the northern side of the lake is largely free of weeds and residents say the fish have grown very large – some are described as “looking like little sharks”.
Residents have been asking Council to fit a grill to the weir so that the carp can control weeds throughout the whole lake and it was put in place last month, followed by the pulling up of the net by Mr Jamieson.
Residents watched on, delighted. Before the fish were introduced, a number of locals had maintained the lake, including wading in and removing weed.
A community celebration will be held at the lake on December 10 with local dignitaries including Rodney MP Mark Mitchell and local board members invited.