Didymo Dave aims to beat the rock snot

David Cade from DOC's 'didymo team'. Photo / NZPA

"Didymo Dave" is an environmental warrior, conservationist and survivor, who protects and prowls central North Island waterways, with the energy of an "Eveready bunny on steroids".

Holidaymakers who flock to Taupo in summer have a fair chance of bumping into David Cade if they go anywhere near lakes and rivers, as he's working right through the holiday period to keep the waterways pure.

Part of the Department of Conservation (DOC) "didymo team" he sees himself as an educator, someone who builds relationships, and a person who cares enough to make a difference to an under-threat environment.

Some don't take kindly to his zealous efforts to prevent didymo - the microscopic organisms of rock snot or Didymosphenia gemitata - spreading to the trout-rich waters around Lake Taupo.

He doesn't care. Gang members don't frighten him, nor do irate athletes or women who stick catfish up the exhaust pipe of his car.

If people are abusive he doesn't take it personally. But you wouldn't want to annoy him - while he was fishing the Hinemaiaia River south of Taupo, a rat ate half his lunch: to date he's killed 236 of its mates.

Until 2000 he was a Thames sharemilker tending to 650 cows. When a mental illness collapsed his ability to work he looked at his life and, lured by fond childhood memories of holidaying and fly fishing, relocated to Taupo.

It took six miserable years before new technology helped him make a full recovery, and now he's working to make up lost time.

He was incensed in 2004 when didymo arrived in New Zealand and began suffocating several South Island rivers in slime.

Fast forward to 2007 and with his health and energy in top form, he joined the DOC's newly formed "didymo team" to keep the slimy pest out of the central North Island.

"People think we're fighting didymo and other aquatic weeds," he says.

"But we're really fighting attitude."

He calls it "conservation intelligence", or lack of it.

As a non-drinker, each week he surprises neighbours by having at least one recycling bin full of beer bottles that he's cleaned up from along the riverbanks.

His other two recycling bins are full of paper, cardboard and cans, similarly collected.

In less than two years he's gathered more 20,000 metres of discarded fishing line which he's shaping into a trophy trout, a visual protest against anglers who choose to leave their nylon behind.

In October, he retrieved two freezers, an old mattress and a bath tub from Taupo rivers.

He says he he's dream-driven, not job-driven. Some might call him idealistic but he can't tolerate the idea of a future degraded environment.

While information signs are fine, he says seeing people do good stuff is far more effective.

With son Hadlee, he's invested hours of personal time working along the Hinemaiaia River, cutting honeysuckle and trapping mustelids, such as weasels, ferrets and stoats.

Catching stoats is a bonus: their tails are tied into trout flies and sold at a local fishing store for $5, with the proceeds going to projects benefiting native birds. He also gets stoat tails sent in from around the country, his latest batch from Hokitika.

Adamant that relationship building is the key to developing conservation intelligence, he bites his tongue with people who are keen to offer him advice, sometimes praise, but who won't break into their "G and T time" to get involved.

In-your-face style doesn't suit everyone, but it's an approach that's succeeded in winning over several of the local tough guys, who he says make great advocates for the "check, clean and dry" ethic of preventing aquatic weed invasions.

And thanks to the New Zealand Ironman triathlon, his reputation has gone global. International competitors in the race, and in other multisport events in Taupo, know to look out for "that mad sod" who dunks their wetsuits before they're allowed in the lake.

At first they thought his wetsuit dunking was a nuisance and there was plenty of dissention.

However, with his belief in relationship-building, whether they've abused him or not, he's out there on race day, banging his pot and cheering the competitors on.

Triathlon New Zealand have now asked for his help to standardise the "check, clean, dry" programme, and compulsory wetsuit dip, at events across the country.

For him, that was satisfaction indeed.

- NZPA