Key to improving water quality is increasing NZ's wetlands - after 90 per cent were drained.
It's not everyone who can relax after a hard day's work, throw out a line and hook a snapper for dinner from their own backyard.
Tapora dairy farmer Earle Wright can. Yet his good fortune is not due to luck or some inside knowledge about a secret fishing spot.
Rather it is a payback for years of effective environmental stewardship of his 120ha farm, a property backing on to an estuary in the Kaipara Harbour north of Auckland.
Wright's cowshed sits about 3km up the estuary and a decade ago this water was practically barren of fish, years of sediment run-off from the land and various land use farms in the district taking their toll on its biodiversity.
But today Wright says the snapper are back. Not only snapper but kahawai and mullet too – and whitebait.
"The place is riddled with whitebait," he says. "They are coming right up to my cowshed, I couldn't tell you the numbers but they are prolific. I didn't put them there, they've come by themselves, I get excited when I see them."
"We have snapper coming back, legal size snapper you can catch. We haven't seen this for 20 or 30 years since the early 60s (1960s). It's really good to see. It's a real positive thing – I don't have to leave the farm to put a line out and catch a fish for dinner."
Wright, who was born and bred on the farm, is one of 15 climate change ambassadors throughout the country in the Dairy Action for Climate Change programme. The programme is part of a commitment by the dairy sector to help farmers understand climate change, the scientific research underway and the environmental mitigations they can carry out on their land to reduce emissions.
Over the years Wright has planted almost 10,000 native trees (mostly manuka, kanuka and flax) and grasses around the water courses and drainage systems on his farm. Land bordering the estuary has been fenced off.
Not only has sediment run-off been reduced as a result. The planting programme has helped cool the water temperature – recent tests show it has dropped by over 3 degrees in the last two years – with the result fish and other organisms have been able to return upstream, nest and lay their eggs before going back into the harbour.
"It's not so much about water quality – although that is important – but about the temperature," he says. "The lower the temperature the better, nothing can live in boiling water and what's living in the water tells me how healthy it is."
Wright, who has a herd of about 300 cows, says sediment loading is the Kaipara's biggest issue: "The catchment is about 640,000ha and 700,000 tonnes of sediment goes into it every year. That's equivalent to 2000 tonnes or 67 truckloads a day."
To measure the impact his methods are having regular testing is carried out to look at water clarity through testing for phosphates, nitrates and other contaminants.
Wright's farm is a flagship for the Integrated Kaipara Harbour Management Group (IKHMG) which aims to showcase good environmental practices by using a paddock-to-harbour approach for dairying.
He is also chairman of the Tapora Landcare Group, chairman of the Tapora Water Users Group and is working with IKHMG to restore Manukapua Island (or Big Sand Island), an area near the harbour entrance which has high ecological value.
Wright says he was inspired to farm in an environmentally sustainable way because he was born in the area: "In fact my waka landed here so in reality I've only moved 7kms from where it came ashore."
His father, who served in the 28th Maori Battalion in Italy and North Africa in World War II, acquired the farm as part of the war veterans' rehabilitation programme ; as a kid Wright fished and obtained kaimoana (food) from the harbour.
"But I've seen the degrading effects of sediment, the destruction of our shellfish and seafood and I thought there must be a better way. I was very encouraged to go out and learn how to farm in a better way."
Fencing has helped control stock and prevent herds from entering the waterways, while a series of culverts acting as sediment traps has helped filter the amount reaching the estuary.
"It (sediment) feeds into three different wetlands on the farm so everything's filtered before it gets into the estuary and the Kaipara itself," Wright says.
A big part of his work is running open days and teaching kids at the local Tapora Primary School about kaitiaki, where responsibility and care for one's own area is at the heart of everything.
"We can't change the world, but if there are issues you can always start by cleaning up your own back yard. That's what I try to impart to the kids and what I have been focusing on for the last 10 to 12 years.
"I think that is the best learning tool a kid can ever see."