Whitebait farmer now focusing on eels
It was 1992: Ruth Richardson had pushed through the "mother of all budgets" the year previous, and Charles Mitchell was fed up.
He'd been working as a fisheries biologist for the former Ministry of Agriculture and Forestry (MAF) for nearly two decades, but things were on the slide.
"They decreed everything had to be an income-generating exercise," Mitchell said.
"Research is where humans are supposed to step forward and make progress into the unknown."
Richardson had no time for that. Neither did Labour finance minister Roger Douglas and his "herd of accountants", who helped usher in a prescriptive, risk-adverse attitude at the ministry, Mitchell said.
At MAF, he'd been responsible for restoring whitebait fisheries, but he could see it wasn't going to happen within the confines of government research.
"I could see the only way of researching restoration was to do it - and pay for it - myself."
He quit and then began to work on a new plan. He wanted to farm the sea.
Now 63 years old, Mitchell has experimented and broken new ground on his own, and largely at his own expense, for more than two decades.
From his six ponds at the far-reaches of the Raglan Harbour, he's successfully spawned hundreds of millions of whitebait and released them back into the ocean.
He was the first person in New Zealand to breed the tiny fish in captivity, and now he's "farming" the ocean for eels.
He's also been growing shrimp on cow dung.
"I'm interested in building new ecosystems, basically," he said. " I'm interested in, can New Zealanders live off our own native biological resources?"
When he bought his property near Te Uku in 1994, it was rough pasture.
A driveway was carved into the hills, a home and sheds were built. The land was fenced and fertilised and gates were installed.
Across the road, where the Waitetuna River meets the harbour, he started to convert the rugged land into a fish farm.
Mitchell said he used his property as a giant experiment.
"My theory was if you had already drained all the wetlands for farms, can you take a small pretty useless area, flood it, and use aquaculture to get as much production off that small area under aquaculture as you would naturally from a huge wetland."
Like many other parts of New Zealand, Waikato's wetlands have been drained and converted to pasture at rapid rates since the 1840s.
Waikato Regional Council estimates that just 25 per cent of the region's original wetlands remain.
"They [whitebait] were a hugely productive fishery back in the day and we've wiped it out. We've done that by our land management."
As a result, the annual volume of whitebait harvested in the Waikato River has plummeted from about 100 tonnes to between 2 and 3 tonnes in the past 60 years, Mitchell said.
His theory, which used aquaculture management of whitebait, boosted the volume of whitebait returning to his farm by two orders of magnitude.
Instead of the eggs developing on flood-prone river banks in autumn - where they could be smothered with silt or polluted by runoff - they developed along the protected pond banks before controlled hatching and release into the harbour.
Five months later, when whitebait swam up river again, they returned to their man-made home.
The whitebait population has improved in the area - and he regularly sells partly grown freshwater species such as inanga and giant kkopu to universities - but Raglan Harbour is unsuitable for whitebait aquaculture.
"Conditions during floods are extreme. I should have picked a site that opened up to the open sea."
He maintains whitebait is a great fish for farming, and his restoration work has been used around the country, but now he's focusing on eels.
"In the springtime, millions of little eels arrive at our coastline and head up the rivers looking for somewhere to live."
Most will die from predators, disease and lack of habitat.
"Our system works based on the smell of happy eels," Mitchell said. "If our ponds are full of happy eels, the little eels come up the river and want to live there too."
In just four to five years, he said, an eel in his pond can grow to the size of a 35-year-old eel in the wild.
It soon caught the attention of the NZ Eel Processing Company.
"The commercial eel processors came and visited me one day and I showed them what I was doing.
"They said, 'If you can grow your's like that, we'll buy them off you'."
He said breeding eels in captivity was virtually impossible, so he's "ranching" the ocean.
Typically, it's being done on a tight budget, but Mitchell said financial constraints had made his projects more commercially viable.
The fish feeders at his ponds are made out of recycled material, and he is always looking at new ways to turn waste into value.
Like growing shrimp on dairy effluent.
"The idea is we take the stuff nobody wants, we grow crops of plankton on it, we feed that into the farm waterway system, which we improve, and grow crops of whitebait and eels on that."
Eventually, he said he envisioned a fish farm could clip onto a dairy farm and provide a productive solution to nutrient run off.
"We can farm the waterways and we can turn that nutrient into useful stuff - into export commodities."