“Just a wee bit further now,” said Dougy, stepping backwards into space and vanishing from view. I clung to a slimy branch and peered after him. He was already 50 feet below me, abseiling down the crumbling cliffside on an old nylon rope. We had descended 200 feet and there was still no water visible through the forest below us, although there was no mistaking the thunderous noise echoing off the sandstone walls of the gorge.

I had met Dougy, an ex-gillie and professional fly-fishing instructor, while fishing on the river Tay in Perthshire the week before. By the end of that afternoon, he had offered to lead me—on the strict understanding that I would not reveal its precise location—to his “secret hidey-hole,” a stretch of highland river containing so many salmon that it was almost possible to scoop the fish from the water with a landing-net. He added that only he knew how to reach the spot, on account of its outrageous inaccessibility.

For anglers, wild Scottish salmon is probably the most highly prized quarry in the world. Enthusiasts pay as much as £1,500 a day to fish the best river-beats at the best times of the year—with no guarantee of catching anything. In 2004, it is estimated that salmon anglers spent £73m on their sport and related services, and caught 93,000 fish—which works out at £800 each. Yet here was Dougy promising super-abundance. His claim seemed improbable. This river was fished by paying anglers up and downstream where the topography was less demanding. And the spot was near a main road. Poachers, I thought, would surely have cleared out such a place long ago.

At length we reached the bottom, 350 feet down. We had to yell to make ourselves heard above the noise of the dark and frothy torrent, as it surged between the rocks. It was noticeably warmer down here. Gnats and dragonflies patrolled the humid air. The gorge, Dougy told me, is an “SSSI,” one of Defra’s sites of special scientific interest, on account of certain rare types of vegetation that grow there.

Dougy retrieved a long metal ladder that he kept padlocked to a tree, laid it over the water, and scuttled to the other side. I followed more slowly, the ladder sagging beneath me. “Extreme fishing,” he had called our expedition earlier, and he was right. A slip now could be fatal. Once we were both across, we scrambled along the slippery cliffside, taking the ladder with us. Fifty yards further on, Dougy laid it down again and we repeated the process three times, until eventually we arrived at an immense waterfall where the gorge opened out above a small pool. The light had an eerie green quality, filtered by foliage overhead. The place felt magical in its sylvan purity; it was a spot for unicorns or Celtic water-sprites.

“Look,” whispered Dougy. “I tell you, John West himself couldn’t fit more in a can.”

I glimpsed the sudden sweep of a mighty fishtail, inches from where I stood. There was a flash of silver as another fish splashed nearby. Then an enormous specimen broke clear of the water and skittered upright across its surface for several feet. Dougy hadn’t exaggerated. The pool was swarming with salmon. Without another word he pulled a telescopic spinning rod from his backpack, and we began to fish.

The trip was not my first contact with the world of salmo salar (“the leaper”). Two years ago, while researching a book on the origin of modern agrochemicals, I investigated a food scare involving Scotland’s farmed salmon. According to a research team led by Ronald Hites of Indiana University, this salmon was the most contaminated in the world. Levels of 14 banned chemicals were so high, the researchers warned, that eating it more than three times a year could increase the risk of cancer.

Given that nutritionists have long considered oily fish such as salmon to be essential to human health, this was quite a claim. The Food Standards Agency still argues that the health benefits of eating omega-3 outweigh the potential risks of contamination. But the Hites report was widely publicised, and sales of farmed Scottish salmon faltered, although not for long. According to the Scottish executive, British consumption of the product rose to 356m meals in 2005, up from 301m in 2003. The British now eat three times as much salmon as they did ten years ago, an estimated 90 per cent of it farmed. Scotland produces 160,000 tons of farmed salmon every year, making it the third largest salmon farming industry in the world, after Norway and Chile.

But the health concerns surrounding farmed salmon have not gone away. In September, the World Wide Fund for Nature published alarming data on chemical contaminants in the human food chain. Every single blood sample provided by 352 people over the last five years was found to contain toxic chemicals. The toxins were placed in eight different categories, ranging from organochlorine pesticides (linked to malformation of the brain) to artificial musks (used in cosmetics and cleaning products, and linked to breast cancer). And farmed salmon was among the most contaminated of the foods tested: it was found to contain traces of chemicals belonging to six out of eight of the categories of poison listed.

When I was a child, smoked salmon was a luxury—a treat that appeared at Christmas or during visits to my grandmother. Salmon seemed to deserve its reputation as the king of fish. Since then, thanks to aquaculture, it has become a kind of junk food, costing as little as 50p a pound. These days it is served at Little Chef restaurants as a healthy alternative to burger and chips.

In summer 2004, I set off on a midge-plagued tour of the west coast of Scotland to investigate the source of this transformation. I was astounded by the industrial scale of what I found. A salmon farm at Little Loch Broom, south of Ullapool, was typical: a dozen vast circular cages, each 50 metres across, and holding around 50,000 fish. The surface of these living cauldrons seemed to boil, especially at feeding time, which was entirely controlled by computer.

The lives of these battery fish—or “sea chickens,” as their detractors call them—were as different from those I saw in Dougy’s gorge as could be imagined. Wild salmon travel hundreds or even thousands of miles in their lifetime, ranging from Scotland to the Arctic ocean. They are magnificent, mysterious creatures whose life cycle is still not fully understood. Farmed ones, by contrast, swim in an endless circle, in an environment that travesties nature. It seemed to me that if pigs or cattle were kept in equivalent conditions—or if farmed salmon were as visible as terrestrial livestock—then the public would be outraged and the market would soon collapse.

Fish-feed, I discovered, is the root of the contamination problem. Farmed salmon are typically fed fishmeal made of ground-up sand-eels from the North sea—one of the most chemically polluted seas in the world. The level of man-made contaminants in sand-eels is tiny, but these contaminants tend to concentrate in fat cells as they move up the food chain—at the top of which, of course, are humans.

Despite these nutritional and animal welfare worries, criticism of Scottish salmon farming focuses mainly on the damage to wild salmon. The campaign against salmon aquaculture is led by Bruce Sandison, former angling correspondent of the Scotsman, whose north coast home I also visited. He noted that wild salmon stocks on the west coast had collapsed in recent years, for which he squarely blamed the salmon farms. The problem with salmon cages, Sandison said, was that they were breeding grounds for parasitic sea-lice, which attacked the wild salmon as they migrated up and down the rivers to spawn. Escapee salmon from the farms, he was convinced, had also interbred with their wild brethren, further degrading natural stocks.

The wellbeing of salmon remains an emotive issue in Scotland. The fish was a symbol of magic and wisdom in Celtic mythology. Sandison’s website, salmonfarmmonitor.org, which receives about 35,000 hits a month, appeals to the country’s sense of its Pictish past. Its masthead reads: “An rud bhios na do bhroin, cha bhi e na do thiomhnadh” (That which you have wasted will not be there for future generations).

Happily, the east coast has escaped the attentions of the fish farmers, whose operations are restricted by government agreement to the west of Scotland. Perhaps as a consequence (and despite some hiccups in recent years), the picture for the most famous east coast salmon rivers—the Dee, the Tweed, the Spey, the Tay and their many tributaries—is rosy. According to biologists’ fish counters on Dougy’s river, as many as 14,000 salmon a year now pass through his secret gorge, more than double the number in 1990.

The east coast has also benefited from the decline of poaching. Twenty years ago, poachers came close to destroying the stocks on Dougy’s river. They didn’t bother with the ropes and ladders needed to reach the pools where the salmon lie. Instead they strung a net across the bottom of the gorge and poured poison into the water at the top. A jar of Cymag—a now banned cyanide preparation used by farmers to destroy rabbits—or a few cartons of household detergent did the job. One gang was caught with 1,500 pounds of salmon, the haul of a single night.

But such unsustainable plunder is a thing of the past. Ironically, it is the rise of fish farming that has driven down prices so far that it is no longer worth the poachers’ while. Moreover, the fish on sale in shops and restaurants these days must come from certified sources, on pain of swingeing fines. It is no longer legal even to sell salmon that has been caught fair and square on the rod. Thirty years ago, poached salmon fetched £2.50 a pound on the black market—the equivalent of £12 a pound today. Yet a modern poacher, according to Dougie, can expect no more than £3 a pound. The consequence was never intended, but the environmental degradation of Scotland’s west coast has been the salvation of the east.

Despite the glut of salmon in the river that day, Dougie and I caught nothing. We tried spinning with a lure and casting with worms—there wasn’t the elbow room to try with a fly—but the salmon, said Dougie with a shrug, weren’t in the mood for biting. It didn’t matter. It was a privilege just to stand in that unspoilt gorge and watch the salmon in action. 

10909498565cc0e095db2852.69530109