Yet it's not all luck. There are ways of shortening the odds, and that's where Harvey comes in.
After a career in journalism, latterly at the Herald (he still writes this newspaper's weekly fishing column), Harvey decided to reinvent himself as the Trout Man and make a living from his passion.
"I don't consider myself a professional guide," he says. "I can't compete with the knowledge of the guides who have been in this region all their lives. But I am good enough to teach people how to fly fish and take them to some of the best local places.
"I saw a gap at the budget end of the market. A lot of people can't afford the rates of the professional guides."
He had been holidaying at Waiteti for several years when Michael, who bought the park, suggested Harvey set up there. Home for Harvey is now a caravan full of rods, reels, flies and various fishing paraphernalia.
Neither is in it for the money. If they were, Harvey would raise his ridiculously low rates and Michael would subdivide and make a fortune. It's a lifestyle thing.
The Waiteti is an idyllic spot with the tranquil stream winding through the campground - very Wind in the Willows. Harvey likes to be up early "to hear the dawn chorus and the stream making its own particular music".
People love the wildlife of the stream, he says. "As well as the king size trout, especially the big browns that can be caught off the holiday park, the stream is full of koura, the freshwater crayfish.
"The ducks are now into their third brood. The ducklings are as big as bumblebees and they drift around on the currents learning how to feed and survive. A lot of them don't survive because of the trout and water rats.
"You can see cormorants diving for smelt, the whitebait-like fish that's the main diet of trout in the lake. Occasionally you'll see a cormorant come up with a trout in its mouth, sometimes half the size of the bird itself. I've seen a cormorant take 10 minutes to get a trout down."
For as little as $25 for two hours plus a licence ($18 a day), with all gear provided, Harvey will teach you the basics and take you to the mouth of the Waiteti, or perhaps to the nearby Ngongotaha stream, to try your luck.
"It's luck combined with skill, experience and knowledge," he says. "You can't guarantee what the fish are doing. Why are they in one place one day in certain weather conditions, and the next day, in identical conditions, they've gone?
"Why are they taking one kind of fly one day and not the next? There's all sorts of reasons and an astute angler will try to work out those reasons."
It's at the Waiteti mouth that I get a hit (well, Harvey gets a hit and hands me his rod). We see it jump and it's a beauty, a seven to eight-pound rainbow.
I follow instructions to give the fish line and let it run. When it starts to tire I keep the line taut and steadily reel it in. Then it's gone.
"Trout are good at getting away, especially from beginners," Harvey says. "But that was bad luck."
The tautness I felt towards the end was not the trout but the line snagged on a piece of wood. Harvey reckons the trout doubled back and found enough slack to work the hook out of its mouth.
So, no fish, but a thrill. "That's what it's all about," Harvey says.
"It all comes together in the moment of the strike, when for a split-second you know you are going to be harnessed to a magnificent wild creature that's about to fight for its life. The universe stands still for that split-second."
More important than a meal then? "Oh yes."
CHECKLIST
Getting there: The Waiteti Trout Stream Holiday Park is three hours' drive from Auckland. Turn left off SH5 to Ngongotaha a few kilometres before Rotorua, drive through the township (the seven-day Four Square there has all the provisions you'll need, including beer and wine) then take a right into Okona Cres.
Where to stay: The park has one- and two-bedroom self-contained motel units and tent sites available. Facilities include a spa, games room, children's playground, fish cleaning area and smoker. There are free kayaks for a paddle on the stream. Fishing licences can be bought at the office.
Fishing: Harvey Clark's fishing tuition and outings range from two hours to a full day at local spots. He will also take keen anglers further afield to the Tongariro River. He has all the gear, including waders, or you can take your own.
Contacts: Phone Harvey on his mobile 021 951 174 or the park on (07) 357 5255.
