Ruaridh Nicoll is the comment editor of the Observer, but little known to his political peers is his obsession for fly fishing. He recently travelled to Bell 2 Lodge in northern British Columbia and this is what he experienced:

I barely remember my grandfather – only that he would clap his hands above his head if I behaved well and, more hazily yet, him turning towards a river, a split-cane fishing rod resting next to his perfectly bald head. I recall my mother far better, although she’s been dead these 20 years. I see her standing in another river, deep in the Scottish Highlands where I was raised, throwing long, looping casts through the September sky. They would ride out over the water and land with barely a ripple.

My grandfather was a talented fly-fisherman, but unlucky. My mother was superb, and lucky. I am a terrible fisherman, but lucky. Hearing that I was off to British Columbia, Canada, on the trip of a lifetime, my friend Olly said to another chum, “He probably won’t catch, cos he casts like shite.” But it doesn’t work like that, as Olly well knows. There is more magic to fishing than skill.

So it was that I found myself knee-deep in the Bell Irving, a river not far from the border with the Yukon. To get in, I had stepped over the heavy footprints of a grizzly bear and her cub, and pushed through a log jam where a beaver was building its nest. The river flowed at walking pace, and when I launched the fly, it swung back across the stream with the smoothness of a hand across the face of a clock. In the way of a heron standing sentry, I let nature reassert itself. I watched a snow shower blur the sky upriver, a rainbow cast outwards over the white-topped mountains and the autumn yellowing of the forest.

And as I let the rhythm of casting lull me, I remembered how, as a child, I found fishing boring – the catching too infrequent and too dependent on the fish. Instead, I would sit on the riverbank with a rifle and try, unsuccessfully, to shoot the salmon when they jumped, while reading Jack London’s White Fang and imagining places just like this.

Then the fly stopped and I felt the weight of a fish turning against the hook. One’s focus shifts fast when fishing and so it was as I raised the tip of the rod. Used to salmon, I kept my hand close to the reel. That was a mistake. In a moment blood was spraying from my finger and the reel was, as they say, screaming.

A steelhead is a big fish, and this one was 7kg. Genetically, it is a rainbow trout but spiritually it is something else entirely. It has travelled out to sea and then swum back, climbing thousands of feet through waterfall and cataract and log jam in its desire to spawn, under the eyes of bear and eagle. Steelhead do not tire easily. Each time I brought her close she would run again, drawing the line swiftly across the pool, occasionally flashing into the air to spin, turn and tumble against the spike. The idea is to do as little harm to the fish as possible, so there was no barb on the hook.

When I was first pondering this trip, my editor, believing one big article on fishing was probably enough for a while, told me to chase my dreams. So I thought about it, and thought about Jack London: I wanted wilderness, powerful fish, and to be as close to nature as is possible. I wanted to be where people normally do not tread. “Puny adventurers bent on colossal adventure, pitting themselves against the might of a world as remote and alien and pulseless as the abysses of space,” as London put it.

North Americans call steelheads “chromers”, because they’re so shiny some will reflect the mountains back to you. This was true of the fish I finally scooped out of the net beside that log jam. The barbless hook slipped easily from her mouth and, having gazed at her in awe, I put her gently back in the stream, a thin smear of my blood on her flank. She waited for a moment in my hands and then, with powerful strokes, beat back into the stream where, soon, she would empty herself of her eggs.

My brother Angus and I had taken a flight out of the horrors of Heathrow, with its shabby, money-grasping departure lounge, to Vancouver, all light, running water and polite officials, where the shops are dedicated to hockey, sailing and skiing. Crossing to the domestic terminal, with its departures to points north, we saw a different kind of traveller: rougher of skin, with heavy beards and wearing baseball caps advertising mining companies and tackle shops.

A two-hour flight, the setting sun reflecting off glaciers and fiords, saw us settle into the damp browns and greens of Terrace, a rough logging town close to the Alaskan panhandle. In the small airport, the car hire woman suggested we watch out for “bear and moose on the road” and laughed, a touch manically. So we set out in the last of the light, slowing only to watch a big bull moose cross the gravel expanse of the Skeena river. The drive to the lodge was four hours and for the last two-and-a-half, we passed no signs of obvious habitation.

The fish we were hunting had been approaching from the opposite direction. Having left their home rivers two to four years before, they had grown sleek and heavy out at sea off Alaska. Frighteningly few return to their rivers to spawn. Only 2,000 a year are counted into the Bell Irving, which, given that the average hen lays 10,000 eggs, is haunting. Our adventure came with a precognition of tragedy, that despite the conservation measures now in place, man-made factors, from climate change to logging, may soon see their extinction.

The Bell 2 Lodge was once a gas station but has grown into a collection of log cabins amid a dense forest of aspen, alder and mountain hemlock. Hunters, tourists and miners travelling the Alaskan highway stop for the superb food and, in winter, a substantial heliskiing operation. The fishing was an afterthought. The owners saw a market not only for taking people out on the Bell Irving, but also for flying them by helicopter to the Nass river, the upper part of which is 100 miles from the nearest road. The fish there are unlikely to have ever seen an artificial fly.

As we ate breakfast, our guides appeared. Steve McPhail and Michael Brackenhofer are dissimilar men. Canadian Steve brings a Zen attitude of “do no harm” to his job. Against attack by bear or bull moose, he carries a small can of pepper spray and what is, in essence, a party popper. Bavarian Michael, on the other hand, carries a short, ugly rifle of the sort the outlaw Jesse James might have used.

Steve took us down to the Bell Irving, reversing his metal-hulled skiff into the clear waters and then, with the outboard fired up, navigating through torrents and placid pools, past the remnants of log jams and under great cottonwoods, yellow in the late September sunlight, while Chloe, his princess of a Labrador, flinched against the freezing spray.

As we powered forward, I realised I was happy: as I get older, I find fishing brings me peace. And I was happy until 9.23am on that first day, because that is when my brother caught his first steelhead. I try to wish the best for my fellow man, but when it comes to fishing, I’m with Gore Vidal. Every time a friend of mine is successful, a little part of me dies.

A couple of days later we headed downhill from the lodge to the waiting helicopter, a Bell Ranger with room, at a push, for five. Angus, a fellow Brit called Nico and I stood nearby, kitted up in waders and the thickest woollens we could find.

“I’m not riding bitch,” said Steve, jumping into the front seat. We packed into the back and lifted off, heading downriver and crossing the forest before climbing through a valley and up into the snow-covered peaks. Between the swirling clouds, we could make out mountain goats on their vertiginous ledges. As we crossed the high passes the tips of the rotors were only feet from the cliffs.

Soon, the weather licked at us and the pilot was forced to circle down a thousand feet into a thin layer of clear air above an exuberant stream.

“Do you think this is the Muskaboo?” he asked Steve. We explored on, across a landscape that may never have felt a human footprint.

“Imagine five guys smoking in here,” said Nico, playing with the ashtray. When the view opened up, we saw a large meandering river, the Nass, and followed it until the water pooled on great gravel beds. Leaves and sticks scattered as we drew down to land. After dropping us, the Bell flew off to collect a raft left downstream by a previous party. “Juicy water,” said Steve.

I wandered up to the neck of the pool, the opposite bank a thick wall of hemlock and cottonwood, and immediately found action. Then Angus connected with an astonishing fish that ran from him for 60 metres or so, before charging back, leaving my brother to grab handfuls of line in an effort to keep tension on the barbless hook. He looked astonished by the battle when at last Steve swept the fish into his net. “This knocks salmon into a cocked hat,” he said.

We fished the Nass for two days, flying back to the lodge each evening. We drifted through pools and rapids on the inflatable, expertly guided by Steve, who also found time to barbecue steaks. Sometimes we would see a moose gazing at us from the bank. Otherwise we were alone. In places, the water flowed so smoothly over the uneven rock it left us awestruck. We could be certain of the presence of the fish in this, their perfect resting place. The fly, a pink piece of fluff I called a Barbara Cartland, would stop, and then everything would explode. If Steve was nearby he would whoop.

In the evenings, back at the lodge, having changed and warmed ourselves by the log fires in our rooms, we would have dinner together. Nico and I argued about global warming, listened to politely by the guides and Sid, the pilot. When we finally shut up, they chimed in, discussing the changes they had seen – from later winters to the way magnetic north has shifted. They spoke with a dignity and depth that made me feel like an urban blowhard.

(Sid would later tell me he had started out mining in eastern Canada, but given it up when two of his friends died below ground. Now his office is the vast expanse of the north beyond the screen of his helicopter. He exudes an extraordinary calm, and an odd politeness straight out of the Coen Brothers’ Fargo. “Are you ready? Rightyo then.”)

On our final day Michael stepped in as guide, taking us back on the Bell Irving. A true denizen of the mountains, he pointed out terrifying slopes high above us that he had skied. He is cutting a five-mile track through the forest so that he can reach the high alp and hunt mountain goats on the cliff edges. His knowledge is both profound and personal.

“The aspen is the world’s largest organism,” he said. “Many, many trees share a root. It is why whole woods can turn yellow at once.”

Those dreams I had had as a child in the Highlands, reading Jack London, were embodied in the way Michael lives. Yet this lifestyle would have a catastrophic effect on most relationships, and certainly mine. The only alternative is to visit, and that requires wealth. Nico is rich enough to come here because he sold a large company in the late 90s. Yet, as Steve pointed out, it is only the money of well-off visitors that protects the life of these extraordinary fish. The loggers would come for the trees otherwise, and the spawning grounds would be destroyed.

On that last day, such privileged access meant we fished close to some extraordinary creatures. A black bear slowly crossed the river above us, looking back only once. At lunch – a picnic of soup, beer and sandwiches – we watched a curious ermine skip towards us through a log pile. It probably fancied a go at my jugular. I caught a final fish, bringing my score for the week to nine steelheads, along with a Coho salmon and a 3kg bull trout. Angus was close behind (ha!). For the salmon fishermen, used to days without catching, this was a dream.

Nothing however, compared with a moment up on the Nass a couple of days before. I had been struggling to keep my footing on a steep bank. The casting was difficult, left-handed into the stream, and I was imagining building a platform in the trees, setting up home, when a viscerally unsettling cry went up. It was the sound that Jack London described: “Palpitant and tense… It might have been a lost soul wailing, had it not been invested with a certain sad fierceness and hungry eagerness.”

I gazed over at the opposite bank and out along the trunk of a long-dead cottonwood walked a wolf. It reached the furthest point and turned to stare over at me. In the face of this, the truest incarnation of the wilderness, I forgot my daydream. Another howl rose from beyond, and the wolf turned and, without haste, wandered back and out of sight.

Written by Ruaridh Nicoll and reproduced by kind permission of The Observer, Sunday 15 November 2009