The Salmon: The Extraordinary Story of the King of Fish

Left behind in the marine larder are the others, the non-movers, growing and growing. Or not growing: some salmon a long time at sea are not especially big. Maybe they too are hedging their bets, passive actors in an evolutionary insurance policy.

A salmon’s eventual size is determined by its length; it can be fat or it can be thin, but without length it can never match the biggest. Girth is the feeding which beefs up the body length. Some of these wintering salmon spend two years in the vicinity of the Arctic, some three, some four, and some even prolong their Arctic sojourn to five years.

Turning southwards as the new year awakens, they ultimately acknowledge the ritual of reproduction, or so it is assumed. Scale-reading shows that after January sea-feeding picks up again following the short winter check. Thus, the fish achieve peak condition prior to the demanding migration south.

Today’s existence is tougher for salmon, for as the northern hemisphere has warmed, dragging the food supply northwards, the return journey south lengthens. Migrating salmon are starting further from home.

Krill may move, natal streams do not.

How long they take to swim home is unknown. Scale-reading differentiates between sea-time and freshwater-time, but we do not yet know in which sea, at what time. Could we? If scales were better able to track diet perhaps we could pin down more accurately how long the journeys take. Sand eels are on known sandbanks and capelin live in the north – the diet could position the predator.

However, there is another lateral-thinking way, a technique not yet fully developed for practical use. We need tags that could measure the angle of the sun at midday, then, as polarised sun filtered through the seawater, it would be possible to calculate latitude. Temperature and the intensity of the light are recordable now; the next step is a reader for polarised light. The tags used on smolts register temperature and depth, but so far they cannot measure the angle of the light. This tantalising technical advance may be not far off.

What is hard fact is that salmon are fast movers. When they do reach rivers they can travel incredible distances in a day’s journey, proven by the presence on them of sea lice. These are saltwater parasites which can only remain attached in freshwater for up to two days. Sea-liced salmon have been found thirty miles up rivers, and more. Fresh from the marine, Atlantic salmon are true Formula One fish, as some sparkling-eyed anglers have cause to know.

They do not, though, just arrive at the mouth of their natal river and motor into it. They savour the moment of transition, whilst making a vital physical adaptation to their water-balance mechanism. In the sea a salmon has to cope with water that is chemically stronger than its own body tissue, making it lose its body liquids. To compensate, a salmon at sea actually drinks seawater, which then passes through its stomach and intestine. Its kidneys expel small amounts of the salt in concentrated urine, conserving some of the swallowed water to make up for the liquid losses.

In his 2009 treasure-trove about the Atlantic salmon, To Sea and Back, Richard Shelton refers mischievously to the ‘uriniferous’ smell of farmed salmon: he has sound physiological reasons to do so! So many fish excreting powerful body wastes in a basin of seawater, only lightly refreshed by the average tides, might well produce some fairly rank odours and taint the aroma of the imprisoned inhabitants.

Entering the milder environment of freshwater a salmon finds its fluids more concentrated, not less, than those of its surroundings. It starts to absorb water through the permeable linings of its mouth and gills. The excess is filtered as dilute urine through the kidneys. So fresh and salt water are quite different environments. Salmon biology has the sophistication to occupy both.

Sometimes for weeks the fish pregnant with breeding preoccupations ride the tides near the river-mouth, tasting the fresh water debouching from the estuary, sampling it, experiencing the reawakening of chemical memories from long ago when they were fish only inches long. The expectant river-runners can be spied from the cliffs above estuary mouths drifting on the tide, maybe fleeing a hungry seal.

The year 2011 was dry for a while in midsummer in Scotland when I was sailing with the life-boat crew along the coast of east Sutherland. On a bright day in a calm sea we approached the River Helmsdale where the boat was to tie up. There, offshore, were leaping salmon, throwing themselves into the air. Those who see this often say they do it prior to entering the river, usually when a freshet of rain has gushed into the sea, bringing oxygen and water particles to their sensory receptors, stirring fusty recollections. Then, often waiting for the moon, they hitch a lift in like any surf-rider, selecting the highest tides.

Just as salmon unerringly follow the shelf-edge off Norway, so they unerringly seem to know what lies up rivers in the hinterland. If a river has lochs and lakes feeding it, salmon swim it earlier, for they can progress to a safe haven up ahead in the expanse of the loch. Scotland’s west coast has what are called ‘spate’ rivers, because they are shorter than eastern rivers, and salmon generally run into them during or after rain when water levels are higher. These fish know there is often no sanctuary or a loch; their only refuge is a deep pool, and it might already contain other occupants. On the River Helmsdale we know from the presence of sea lice on fish caught by anglers that many salmon run straight through the 24-mile system and forge on through the fish-pass into the chain of lochs at the top where they can safely bide their time until autumn spawning.

The river system made in heaven is perhaps the one with big headwater lochs providing a sanctuary for the salmon and an inducement to run the river to get to it, thereby presenting anglers with chances of an encounter. Even better, possibly, would be the system with a big loch in the middle, with salmon filtering into it from below and out of it from above, the loch also acting as a natural regulator of water levels.

Sometimes forgotten are landlocked salmon. They lack the mystique of the ocean rover, and they do not leap waterfalls to remind us of their grace and power. More importantly they do not have to worry about smolt losses to cetaceans, Russian trawlermen or any other conventional threat. Pike with backwards-curving teeth might be their toughest adversary. In addition they need none of the adaptive mutations for moving between saltwater and fresh.

The lines are not hard and fast. In anadromous salmon populations some parr never leave their rivers and behave as landlocked salmon, awaiting the return of gravid hen salmon for their sneaky off-chance at fertilising the next generation.

Perhaps it should not be surprising that populations of landlocked salmon comfortably survive today. In Norwegian, Swedish and Russian lakes there are landlocked salmon as well as in North American ones. These northerly receptacles of cold water never heat up too much for salmon’s tolerance. Landlocked salmon could be compared to brown trout, happy not to migrate whilst some of their siblings run the gamut of the wilds to become sea trout.

Norway’s huge Namsen River has a majestic and impassable waterfall. Whilst I was watching its awesome power and letting the physical reality of the cascading torrent sink in, the droll ghillie told me that only the week before a visitor angler playing a feisty salmon from a downstream-drifting boat above the fall had failed in his battle-concentration to notice the advancing roar of the crashing water. He went backwards over the top, attached with his fishing line to the fish of a lifetime, and was never seen again. The story was relayed with barely suppressed ghoulish relish. Did he get his kicks telling that story every week? At any rate, above the Aunfoss waterfall subsist the resident salmon which never migrate, cut off by a giant curtain of cascading water.

Landlocked salmon are not uncommon in North America. In Idaho I have seen the scarlet kokanee, which are Pacific-origin coho salmon, and I found the sight somehow disturbing. Here are these small shoals of highly coloured fish in the translucent shallow waters of rivers and lakes, looking nervous and wary. You sense they are trapped, freakish prisoners, despite their presence having been determined by ancient geology. Really, they are true and admirable survivors, but it does not feel like that. And their chromatic violence in the drab landscape adds to a sense of displacement.

In Lake Ontario the early settlers found landlocked salmon weighing up to forty pounds. So much for the sea only being able to build up weight; pike disprove that and the lake salmon underlined it. These monsters, however, are now gone. In Maine the landlubbers are called ‘sebago’, being the name of lake in which they were first identified, and in other Maine lakes there are different varieties of salmon non-migrants.

To an angler a salmon is in its natural place in a river. That is where an encounter can occur. A river is the proper mis-en-scene for connection with the fish by a wispy length of nylon on a bendy stick, and a hook maybe no bigger than a gnat. What salmon do in rivers is a subject upon which fishermen have ventured opinion in a veritable lexicon of viewpoints. Seldom has so much speculation been focused on one inhabitant of our environment. How many shelves could you fill with the books which have celebrated the mysteries and majesties of moles, rabbits or hedgehogs?

Long ago debate centred on whether salmon eat in rivers. It seemed impossible that a large creature could enter a river a year before undertaking the rigours of spawning and live off its reserves. Anyway, why did they take fishing flies if they were not eating?

Peter Malloch, as Scotland’s Inspector of Fisheries, seemed to have nailed the matter way back. He and his team eviscerated thousands of salmon. They never found anything in the stomachs, no matter how long the fish had been in the river. Even if, as happens in a few places, salmon over-winter in a river and do not spawn till late the following year, they still do not feed. It is a stupendous fast. However, it failed to stop many subsequent armchair theorists raising spectres and postulating that salmon must eat, that sundry reasons existed for their stomachs being empty, that what was evident knowledge was as full of holes as a colander. The fact, amazing as it is, remains: salmon cease feeding in freshwater. Like snakes, which can live for months, even years, without eating, salmon subsist on their stored marine reserves. If they open their mouths to seize fishing flies in rivers, fishermen may claim they have been artful enough to override behavioural rules; angler achievement is all the greater. Not quite as great, though, as the biology of their quarry.

An area for debate between anglers and salmon professionals is whether the leaping salmon is moving upriver or not. So many times ghillies and anglers talk of ‘fish running’, meaning they are ascending the ladder of the river-system. But if you watch salmon from under a river at their level, as is possible in the riverbed salmon museum on Sweden’s River Mörrum, you see that jumping salmon may move slightly forwards from where they took off but they drift downwards as they descend in the water-column, landing back on the launch pad. Salmon maintain their station more than some of their aerial antics would suggest.

Whereas anglers believe that salmon are running past them, and sometimes try to hasten upriver and get ahead of them, river counters using electronic beams show that salmon ‘run’ mostly at night. Summertime salmon almost invariably use the cloak of darkness to hide their journey. Some counters work with parallel sets of beams, interrupted beams signifying a fish swimming upriver. Counters can be calibrated so that only fish of a certain size register, excluding smaller ones and trout.

In Canada counting salmon in clear-water rivers can be unfussy: I have seen a wide placid river where the flow is channelled into a central funnel and a human counter perched on the platform end working a clicker to record every fish passing. These wilderness workers, operating in rotations, need good bug dope, a wide-awake buddy checking for bears tiptoeing down the platform, and extraordinary concentration. Happily the runs are often focused into just a few weeks, and, pressed for time, they move in the day.

More usual aids are military-type night-sights, which, focused against a light background, make salmon watchable as they swim upstream. Most of those fish leaping under the noses of anglers are not moving upriver but performing their acrobatics for other inscrutable reasons. Nineteenth-century writer William Scrope charmingly referred to them leaping because of ‘excitement’.

Again, anglers talk of fish running in spates. They actually wait until the debris and clouds of suspended particles have ebbed and abated and then they run, in the cleaner flow. It is dangerous for salmon to get muck in their gills, and as birds constantly preen their feathers for efficient propulsion so salmon look after the efficiency of their highly tuned bodies. One or two days after the flood-crest is a likely running time – and they are slower to chase a melting snow spate than a rain-driven spate.

Where anglers are spot-on is in the commonplace assumption that salmon get interested in fishing flies after they have moved position. A salmon that has dwelt in one place for a month may have watched innumerable flies swinging over it and pays them no greater attention than the man on the park bench does who subconsciously watches buses looping their circuit. The same fish having shifted station will be activated and lunge at the fly, maybe attempting to purify its new location of annoying irritants.

Tagging has shown that salmon often enter a river, stay a while, and then leave it. During a long summer salmon may climb rivers, fall back to brackish estuaries, wait for another oxygen-rich freshet to stimulate a move upstream again, and then repeat the yo-yo procedure. Although Atlantic salmon are renowned for their generally faithful return not only to the river of origin but to the section of river from where they broke out of the egg, they can mess with the rules too.

A salmon has been tracked tasting the water on Scotland’s west coast for a while, then moving to an east-coast river, and finally ascending the third river it had trialled in one year, where it spawned. This ranks as an extreme example of genetic straying. A salmon tagged on the Dee in Wales was re-captured in Denmark. I am unsure whether a salmon tagged in Europe has ever spawned in North America; reports vary, but betting against salmon’s versatility and survivor-adherence would be a mistake.

I was on Russia’s Kola Peninsular on a river called the Kharlovka in low-water/high-temperature conditions when it appeared to the anglers and the ghillies that the fish actually left the river, retreating to the refreshment and oxygen of the open sea. We could see them driving downriver. At this point the sea was only a mile or two distant. There would be a good enough reason: when wild salmon are closely confined fungal diseases spread fast. They can spread even faster amongst fish in low water and even disfigure a whole river population. Saltwater does the laundry.

Salmon fungus comes in more than one type, and can keep growing on fish that are already dead. The fungus is an external manifestation of a fast-spreading microbe. It is normal even in ordinary seasons to find pre-spawning salmon with white fungus starting on their heads and backs, and when spawning is done these mouldy discolorations accelerate to be abrupted only when the fish is cleansed by saltwater. Warm, low-water river conditions make matters worse.

Managers report that this occurred on the Tweed in Scotland late in 2011. It was not the potentially lethal condition called ulcerative dermal necrosis (UDN), in which lesions can penetrate into skeletal tissue, rather, as assessed by the river biologists, a more common fungal affliction broadly termed Saprolengia, caused by overcrowding.

The last time fungal diseases killed huge numbers of pre-spawners in Scotland was in the 1960s, when runs were prodigious. I remember walking down to look at the water in August with my grandmother, a dedicated angler who went to the river as others go to their office. White lethargic salmon with rot peeling from them cruised aimlessly in shallow water. I recall her sombre mood. Some see fungal outbreaks on a major scale as a response to over-population, and this distressing scene did indeed coincide with a heavy run of fish. Widespread fungal attack has not recurred on this river since.

Fishermen are the best monitors of a river-system. Their observations and speculations about this fish serve the species well. What salmon do in rivers will probably preoccupy anglers for as long as they persist in trying to catch the fish in what might be seen as an elaborate manner. Easiest perhaps then, sifting the options for evidence, to watch salmon in rivers.

I remember meeting a German salmon angler in Ireland long ago who had adopted a rigidly logical Teutonic approach to his fishing. Having showed me a rack of twenty-foot rigid poles, he asked what I thought he did when he went fishing. As if it was the most obvious thing in the world, he cried, ‘I climb a tree!’ When sun shone on the pool he was to be located hanging out of his tree wearing polaroids. From above, the river was like glass. For this Germanic genius it was self-evident that to cast into a river in the hope of catching a fish you did not know was there amounted to a bizarre and undignified expenditure of energy. So he looked down from aloft and spied, from his vantage points along the River Blackwater, whether any salmon were available for the catching.

He then drifted flies, of his own special construction, of course, over the noses of the targeted fish until they lost patience and snapped. Invariably, he assured me, they all eventually break, irritated to a frenzy, like a person with a spider crawling on his face. The idiosyncratic sportsman claimed to have caught numerous fish in this manner. He said snapping-time was always inside three-quarters of an hour.

Thinking on it, catching them on those rigid poles must have made it a mechanical exercise, lacking in the intimacy of galvanic contact. But there was the hunter satisfaction, I suppose, of having behaved in an impeccably rational manner.

I recall a scene one summer on the Saint-Jean River in Quebec where the water is pellucidly clear. I was walking down the river-bank when I came across an angler lying atop a small bush with his hat tilted over his eyes. Striking up a conversation it transpired he was waiting for ‘his’ fish and the right moment. I pressed him more and he showed me the fish, which I took a while to detect. Stretching far out in front was a rippled pavement of smooth, light-coloured rock. The water looked shallow, maybe three feet deep. Eventually I spotted, nestled into what was no more than a groove, a very large salmon, its back beautifully camouflaged in the ochre tones of the undulating river floor. The angler said he had tried his fish earlier in the day with the sun just rising. The fish had moved and moved again often but never opened its mouth. The next suitable moment would be as the sun disappeared over the canyon side. The angler had six hours to go. He seemed unruffled at the prospect, and sure the fish would succumb. He intended drifting his fly down from some distance above to give the big fish time to see it, and then letting it slide over his nose closer and closer, till … the chapter was written in his mind before it had even taken place.

The interesting time for salmon-watching is late summer when numbers are building for the orgy of spawning. Upstream of the river-bridge to my home is the entrance to a tributary. Salmon gather below the bridge for the shade, perhaps, but also to wait for the right moment to run the tributary and spawn there. The place where they accumulate looks the same as the rest of the river-bed, a trifle deeper maybe, stones studding the sandy bottom. They have stations, places they like to be. These are not, as is often loosely said, ‘behind’ rocks, rather to the side or below. There they rest, pointing upstream, close to the bottom, occasional bubbles emerging lazily from their mouths, like giveaway wisps of smoke from rainforest tribes.

In the protection of this shady place at a certain point in the autumn the salmon numbers stack up in a diamond formation. To start with, a few just take positions here and there, but as spawning approaches they tighten into a formation. As the days pass and no rain raises water levels, the space they are occupying shrinks and gets cramped with more fish still arriving. It is like a rail terminus with no trains leaving. The water lacks the refreshment of oxygen. I have seen the mass of salmon get edgy and impatient; they start to jostle and swirl at each other. There is a palpable build-up of nervous tension.

One time this was dramatised in a remarkable way. Above the bridge swam a pair of mergansers, paddling on the side of the river. Like a torpedo in an old war movie, a large fish suddenly charged the two sawbills. He launched himself from at least 60 feet and, missile-like, broke the surface enough to create a bow-wave. The mergansers, sensing something at the last moment, rose in a panic of clattering wings and flew fast away.

Well, salmon do not in theory attack birds, but the fact is that mergansers are major predators of salmon eggs, a difficult enemy for the progenitors because the sawbills get their necks and beaks under the water and then shovel through the redds removing the buried caviar. Salmon hide the eggs in their redds and assume they are safe until the little alevins wiggle out in warming springtime sunshine; they cannot remain on duty to stand guard. I have seen a merganser in Canada surfacing from redd-raiding with salmon eggs cascading down its chest. I believe that cock salmon recognised in the merganser pair, with their elongated predator shape and thin heads, a predator enemy. It was a bird-fish interaction I will never see twice.

Prior to rain, the petulant salmon under the bridge are all moving and all disturbed. They squirt forward and drift back, they nudge other salmon, their tails swish and they shift position. Rain falls. I wait for the right conditions to see under the bridge again, despite it being harder with higher water. One time I had counted around 150 salmon in diamond-formation then, following rain, the river-bed where they had been was denuded of every one. The breeding pack had moved on to the final stage: the upper tributaries and the redds.

I was taught by an old fishing ghillie how to read water at this point in the salmon chapter and to detect the presence of a river’s spawners from water movement. It is an art. You walk upstream from below, although from above is possible too. The spawners are in certain types of places, at least where I view them they are. They occupy the fast water beside and behind the bigger stones – they like active water with energy. To start with they are not in the fastest riffly current, which is shallow, but in the channels by big rocks. From below you see not the fish but the bulge in the water above where they lie. Their bodies are never long still, so the water has a thicker, darker look. Momentarily they move and a fin-edge shows. Then the fin of the partner fish, close by. If you walk up the bank opposite to the fish you can watch the pair of them. Only if you wade into the water do they swim off. It is not like in the fishing season; these creatures have a special matter on their minds, nothing less than their definitive act. As spawning time approaches they move into the faster riffles.

In Canadian fishing huts and fishing lodges and airports near fishing rivers, one man’s quotations often adorn the public spaces. They are the words of Roderick Haig-Brown, a judge in his day and resident on the banks of the Campbell River on Vancouver Island. In his book Return To The River he describes the drama on a spawning redd of a female Chinook salmon, a stupendously big fish for the little rivers it breeds in.