Latest News Fighting Nature with Nature - Hungry Fish to Restore Lake Hungry fish will hopefully cure Henley’s Lake’s weed problem. Hundreds of grass carp are set to be released into the Masterton lake in a bid to clear the weed and make it safe again for recreational use. Parks Manager Grant Hathaway says the introduction of the Amur species of fish won’t be problematic because grass carp already live in the lake, a legacy of the last attempt to clear the weed 16 years ago. “However, they didn’t put enough in last time so those that remain are rather large but the weed is still a problem. We’re putting 500 in this weekend and their health and numbers will be closely monitored by our supplier,” Mr Hathaway said.  Consent to release the fish was granted by MAF.  The Council received a report from officers in May and adopted the recommendations to proceed as soon as the fish were available. Mr Hathaway told the Council at its May meeting of past efforts to remove the invasive weed, including the use of:  · Volunteers, council staff and contractors to mechanically remove weeds with wire and grapple equipment, usually with only limited short-term benefit. · Helicopters to apply chemical spray, in particular Diquat. This was reasonably effective for several months on some species of week. However curly leaf pond weed remained resistant and continued to interfere with recreational use of the lake water. Last time an attempt was made to eradicate the weed using carp, only 20 fish per hectare were introduced. “This wasn’t enough and we’re finding weed growth in summer is particularly problematic and off-putting for lake users.,” Mr Hathaway said. New Zealand Waterway Restoration Ltd (NZWR) will release the 500 Amur fish into the lake this weekend (Saturday June 6). More will be added if a survey in September shows the 500 hundred hungry mouths have not started to get on top of the problem.  NZWR will own and manage the fish stock and has a five-year contract with the Council. They will carry out surveys and report back to Council. “This method of aquatic weed control has been used successfully elsewhere in New Zealand and overseas. Auckland City Council, Manukau City Council, Franklin District Council, and Environment Bay of Plenty also use it.  “These are not pest fish and will not breed in New Zealand waterways.  We already have escape netting over the lake entry and exit points so the infrastructure is already there to support the new arrivals.  The Council will pay $13,750 for the first year of the contract and $10,000 each remaining year.       For more information about the fish, go to www.nzwaterways.co.nz/ 3 June 2009