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The Salmon: The Extraordinary Story of the King of Fish
Michael Wigan
‘Sometimes the river was too high to see the fish pairs well, sometimes the wind shook up the surface too much to get a clear view. You know if they have already spawned and buried their eggs in the gravel because hit by the light they run, and squiggle downstream. Un-spawned, they face the light. It is one of nature’s great spectacles.’So begins Michael Wigan’s fascinating journey into the extraordinary world of the king of fish. He explores the natural history of the salmon, this most mysterious of fishes that has fascinated man for centuries, evoking passion and adventure throughout the ages.He explores the life cycle of the salmon, weaving his own experiences and stories into an evocative narrative. Crucially, he addresses the pressing matter of conservation issues and human management, which in the past has led to fast decreasing populations. History suggests it is the pressure of human development which has narrowed down the survival zone of the salmon, and the author questions whether we can go on altering natural systems and freshwater rivers in order to make space for human populations, and do so in sync with fish needs.In his unique and passionate voice, the author transports us to another world – his writing is beautifully evocative and his excitement for the salmon palpable throughout.
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To Robert Pointon and Hugh Ardagh, my two teachers at Sussex Tutors in Brighton, England, who taught me how to appreciate literature and write clean English. I hope I have not let them down. Neither, as far as I know, had any interest in fish. The desire to communicate precedes having anything useful to say, as anyone in the pub before closing knows.
Contents
Cover (#u0c0d055d-3421-5a15-ab8e-334b7262dae9)
Title Page (#u8d016716-9e5b-59b7-a049-f89ce895e2fd)
Dedication (#ulink_6a8106aa-0408-5b0c-a171-5f9e58bc442d)
The Journey (#ulink_83ad07c2-b743-56f1-a44d-ae331971f7ff)
The Culture (#ulink_262a4950-89b9-53fa-9e69-1d29973a5dd1)
No Admission (#litres_trial_promo)
The Passion (#litres_trial_promo)
The Pressure (#litres_trial_promo)
Extinction Vortex (#litres_trial_promo)
Survive or be Damned (#litres_trial_promo)
Further Reading (#litres_trial_promo)
Acknowledgements (#litres_trial_promo)
Index (#litres_trial_promo)
Picture Section (#litres_trial_promo)
About the Author (#litres_trial_promo)
Copyright (#litres_trial_promo)
About the Publisher (#litres_trial_promo)
The Journey (#u07d98b94-28b9-5a1f-9881-266326795b2f)
The night is overcast and promising. I packed a large spotlamp, reserve mini-torch and windcheater into the truck and chugged 5 miles through the blackness up a track to a high tributary of Sutherland’s River Helmsdale, in the north highlands of Scotland. My destination is an isolated spot, several miles from any road or house. I could only feel a light wind, which is good for salmon-watching because wind-ruffled water obscures the fish-action.
Painstakingly I checked a stretch of river, as I do every year, for numbers of paired salmon preparing to spawn. This section of the river has excellent pebbly expanses of small gravel in which salmon like to make their nests or ‘redds’, and year after year I have found salmon in couples side by side in the riffly bits behind large boulders, facing upriver. They are unworried by the bright light, instead focused on the act which ensures that their genetics pass down and that their own progeny will one autumn occupy that same riffle and reproduce there too.
In the spotlight you can see everything; the markings on their backs and their rich tartan bodies – which by this time of year are red and black and magenta – the heads of the cocks in luridly contrasting colours, and you see their tails gently finning in the current, steady as metronomes.
But tonight there was nothing there. The pools were empty. It was easy to see because the water was low, lower than I had seen it before in November – which is a wet month hereabouts.
Then I heard what sounded like hooves crashing through water. I thought I had winded stags, for some of the red stags come to the river’s edge at this intersection and they run from human scent. I thought a small party had crossed the river below, so I walked down the bank.
In the radiance of the powerful spot-light was a striking spectacle. A salmon on its side was arcing in a shallow pool, its body bent like a bow. The sound I had heard was the smacking of its body back against the water. I looked closer. There were two, a cock and a hen, small-sized. They had swum up the river this far to find suitable redds, prompted by the echo of their own birth in this tributary, maybe in the self-same stretch, in an earlier time. But the pair was marooned. They had got this far and the frost had driven the water level down as they waited to reproduce, while below them the riffly water was even slower. When salmon swim through low water the mucilaginous slime can be scraped from their bodies, exposing them to infections. It was hard to go down and impossible to go up. This pair had traded on rain and been let down.
Undeterred, they were spawning anyway, and she was busy laying eggs with her shuddering body ejaculating the pink globes into a groove in the pebbles. I was watching a heroic act of self-replication.
Presumably the rest of the normal number, maybe a dozen pairs in a three-hundred-yard stretch, had dropped back as water had shallowed. Indeed, that appeared to be so because in the main stem of the river there were salmon pairs all around. Some sections were a maelstrom of spawners, cramped for space, elbowing and shoving each other to get at the good clean gravels.
The air was chilling down. I clambered back into my truck and thought. This was a new event; sometimes the river was too high to see the fish pairs well, sometimes the wind shook up the surface too much to get a clear view, but in the best years you could look down on the spawners as if in an aquarium. You know if the fish have already spawned and buried their eggs in the gravel because when hit by the light they run and squiggle downstream. Un-spawned, they face the light. It is one of Nature’s great spectacles.
For the salmon is natural royalty – no other fish has excited human interest to the extent that Salmo salar does. Let’s tease out the mystique which has resulted in salmon-fixated anglers, in salmon-bewitched writers, in salmon biologists and random salmon-dreamers.
This is the fish that connects land and sea, it is our bridge with the maritime, and the sea is twenty-first-century man’s largest getaway. Anyone can find a boat and go out there, un-harassed, free to turn left or right or go straight on. The salmon is an emissary from this vast fecund zone, where the occupants are out of sight beneath the waves. This is the place where salmon accumulate their fat and gain body weight. It is where they feed to become some of the fastest swimmers anywhere. This is the place salmon acquire the condition that allows them to leap waterfalls, moving up rivers to re-visit their birthplace.
I have just seen the highest waterfall in Scotland which they can ascend in one mighty leap; it is 12 feet high and vertical. To help their passage the local fishery managers dam up the water in the pool below, raising its level by four feet, so that the homing salmon has a mere 8 feet to leap. Olympic athletes would balk.
I was told that the fish poke their heads out of the water and inspect the situation before assaying a leap that must cost them their last ounce of energy and strength. Then they use the upthrust from the deep boiling of the falling water to kick with their tails and twist their bodies, arrowing through spray over the lip of the ledge above. No wonder people marvel – a fish that flies!
What these fish are conveying to the upper reaches of natal rivers is a food-load accumulated in or near the Arctic Ocean. Many salmon from the American and Canadian north-east, nearby to an older class of European salmon, winter close to the shore of western Greenland. Here they gorge on krill and shrimp and capelin, small fish packed with nutrients that can be converted into body weight and condition.
It is known now that to find the food supply salmon use temperature bands as trackers. The presence of salmon is dictated by the food supply, and that is determined by seawater temperature. Lower temperatures mean slower growth rates, smaller egg sizes and later development, and smaller size can expose them more to predation. In the 1990s scientists found that capelin off Newfoundland spawned a whole month late owing to very low temperatures in spring, which would have had a knock-on effect for salmon. In this way a seasonal shift in the behaviour of prey can be critical for the body condition of salmon needing to bulk up for the journey home.
Salmon eat molluscs, worms and other fish at sea – even insects which land on the surface when they are near coasts and winds are offshore. It was always reckoned that salmon were opportunistic omnivores, and recently it has been found that their wide-ranging diet embraces lanternfish. These strange-looking denizens of the deep rise to the surface at night to prey on larvae and other floating titbits only to be intercepted by any foraging salmon as they come up.
Researchers were surprised to discover that this hunt was prosecuted even at considerable depths. Previously thought only to happen near the sea-surface layer, it transpires that salmon dive, and dive far. How they detect prey in the lightless deeps is unknown, but presumably they use echolocation or other senses so far unidentified. The behavioural picture gets more complex. Not only do they travel thousands of miles between feeding and breeding grounds, but they go downwards too. They touch our planet at its extremities.
Some of this adventurism helps explain their mighty grip on our imaginations.
The range of the fish is one of the factors. Not only does it span the north hemisphere from top to bottom but its potential larder is three-dimensional. Many animals can only find food to left and right, but salmon do so in all directions. Like birds in the air, they are free on all sides, yet often they end their breeding cycle in streams that a person could step over – so narrow they can barely turn their bodies round. Instead of turning, having spawned the fish still face upstream and drift down backwards with the current, often patched with fungus, half-alive, half-decaying. Using their salty environment as any rotational wild grazer uses its range, meeting appointments with feeding opportunities at different points, the fish climaxes in cramped confinement. Tackling lanternfish at depth, they reproduce in shallow stream-water often only half-submerged, usually under cover of darkness.
It is the transport of sea protein to the headwaters of rivers deep inland that completes the bridging of maritime and terrestrial. For the bodies of the deceased salmon that expired after spawning are deposited into an environment often starved of protein enrichment since the movement of glaciers down to the coast thousands of years ago. The residues of those shrimps, molluscs, fish and worms which have built our silver wanderer fall from its decaying carcase, seeping into the impoverished soils of the headwaters.
This is more strikingly so with the cousins of Atlantic salmon, the species inhabiting the Pacific and the American West. The largest of the seven species, kings or Chinooks, are physically bigger, but all Pacific species lay more eggs and are in greater abundance than Atlantics. Crucially, none of the Pacific species makes it back to sea; they all die after spawning inside the river-system. So when millions of these fish expire in the forested headwaters of British Columbia, Alaska, or the other states of the seaboard USA, it is equivalent to fertiliser dumping along riverbanks on landscape scale.
Certainly, bears and eagles, wolverines and carrion-eating birds all feast on salmon remains in the spawned-out cemeteries where their lives ended, but for these species too this is body-building prior to the onset of harsh winters, with protein originally gleaned from the sea. A neat protein transfer has hitched a ride on salmon.
People conjecture whether the original runs of Atlantic salmon into the rivers of Western Europe and Scandinavia may have equalled in mass what still occurs in the western Americas. Not only were the numbers of Atlantic salmon on a different scale to those of today, but so too were their dimensions. In 1885, near Rotterdam on the Rhine, 69,500 salmon were netted with an average weight of 18 pounds – a size approximating more to that of a Chinook than a modern-day Atlantic. We will never be sure what the volume of primeval runs into Europe were, except that they were spread over all of the western coastline and in infinitely greater numbers. But in 2010 I gleaned an idea of what the scene must have resembled at the foot of a lake called Meziadin in British Columbia in late July.
I had been fishing for steelhead, a sea-running trout, with Walter Faetz on the Bell Irving, a wilderness tributary of the major far north river-system named the Naas. Walter said he wanted to show something to my fellow angler and me. We drove an hour, drew up on a lakeside and launched a small boat. First, Walter motored up-lake awhile and we saw restless sockeye salmon packed in the outflow of a small river waiting for rain to allow them to run it. Then we chugged down the placid un-peopled lake to the outflow.
Here was a stretch of tumbling water, then a small circular lake maybe two hundred yards across, debouching through more rocks at the corner. Gaunt pines surrounded a scene of primitive energy. Vaulting into the air at the top end were vast fish appearing like polychrome Zeppelins out of the burbling water, to land again where they had lifted off. In their dying livery of magenta, crimson and mottled sick-yellow, king salmon lunged from the flowing river, lying down on it again and gradually submerging as if in slow motion.
In our small inflatable we paddled over where they lay. White fungus was growing on their fin-edges and backs and also on their heads. They were disintegrating whilst alive. Underneath the boat and to either side, they were flopping and swishing, listlessly lunging at each other, indifferent to our presence just feet away.
Across the current played out another enactment. Here was a long ridge of freshly churned gravel, and from its whiteness and lack of algal covering it was clear the gravel had been recently ploughed. Gently finning in the few feet of water above it were hundreds of bright crimson sockeye salmon – another, smaller species of salmon from the Pacific. The fish were stacked in layers, like wine bottles in an invisible rack. If I had got out and stood on that gravel-bank I would have surmounted millions of eggs promising the next generation of sockeye in this fecund river. Patiently awaiting our departure perched bald eagles looking huge in the spindly pines and gloomy light, preparing to compete with the patrolling grizzlies for the dying salmon. Compute the volume of fish-protein in that modest body of water and the mind boggles.
None of that protein richness would leave this environment; it formed part of the ecology – sea refreshing impoverished land far from the coast.
Out of interest I procured facts from the government website which records annual runs of salmon at a fish-pass just below Lake Meziadin. We drove there and saw salmon leaping in futility against the dam walls, others catching the faster water on the side where the fish-pass laddered its way up past the dam. The number of Chinooks that ran this branch of the Meziadin River was around 500, the number of sockeye around 200,000, and the coho run around 4,000. The River Meziadin is small – my fishing partner and I easily cast line across the central river-flow – yet the fish biomass on the redds in the autumn, acre for acre, must approximate to a beef feed-lot in the American Midwest.
What we witnessed was fish abundance from another epoch. It was part of a wider picture; that year, on the heels of scientific predictions of a diminished sockeye salmon run, in fact some 24 million fish showed up. Scientists sucked their thumbs. Fish are a jump ahead. It is tempting to wonder how close that scene with Pacific salmon in British Columbia paralleled in abundance what occurred in western Europe with their Atlantic cousins over 10,000 years ago, before human impact.
It may not only be the soil and avian predators that benefit from this transport of protein from the sea. In British Columbia, amply funded for fisheries research, it has been found that in their first year of life out of the egg, young steelhead a few inches long subsist largely on ‘spawner-derived’ feeding. After one year of age, 95 per cent of stomach content was proven to be from salmon eggs and carcases. This was discovered by tethering 400 dead salmon in a river and testing the stomach contents of young steelhead living downstream of them. In other words, they too were nourished on dead salmon at a critical development time. Related to salmon but not the same species, these migratory co-habitants would seemingly struggle if the big salmon runs disappeared.
Is this the case with Atlantics, our European species? Do their descendants subsist on their shredded flesh? No one knows.
The charm of the Atlantic’s salmon is that a small percentage do not die; having spawned, some survive. It is thought that around one in twenty live to spawn twice, and they are mostly females. This simple fact changes their whole definition from that of their Pacific cousins. Their softened bodies roll with the current towards the sea. Able to move pigment around their bodies, they have changed colour throughout their lives – in sandy-bottomed streams parr colour up sandy; put a cock salmon in a dark tank and cover the top and it darkens, faster towards spawning, but take him out and he pales. Now the sea-seeking fish silver up, fresh-minted; their bodies carry a latent promise of recovery, return and procreation again. Ancient Egypt’s Pharoahs would understand: they have an afterlife.
The passage to recovery is far from safe. Otters find them easy prey. Raucous gulls tug their barely sentient carcases from the shingle and devour them. Crows patrol the river edge for prey, squabbling over the rotten bodies. If any fortunate fish do manage to reach the ocean they run smack into hit-squads of patrolling sea mammals, in the form of grey and common seals. These far larger creatures can catch salmon by slashing them senseless with their flippers, and in a copy of sea-lion acts in the zoo, they flick them into the air, strip off the skins and swallow them as they fall.
The two seal species have protection in Europe, enjoying an almost complete prohibition on culling. Not consonant with the heavily managed catch quotas for all commercial fish, this status of sanctity and exclusion from management has its origin in the excesses of the whaling industry long ago. Whaling desecrated the populations of one of the world’s largest and most miraculous beasts in a hell-for-leather (sic) war on natural resources that has no historic parallels for goriness and intemperance. In the case of the American buffalo, one species was hunted down; in the case of the whales, several species were decimated. For whales are ocean mammals which have to surface and can therefore be seen. The oceans were raked and re-raked until almost none of the species with value were left. The scars from that era have entered Western psyches and will be a long time healing.
Seals are the major predators of fish close to the coast. Commercial fishermen have shown that they eat far more of the fish in the North Sea than fishermen are catching. However, for the time being the images of whiskered recumbent lumps straddling offshore rocks, doe-eyed saltwater Labradors, is forceful: they are sacrosanct. The only shots they have to put up with are from cameras. There is no public appetite for the resumption of anything that could look remotely like whaling, with any sea mammal. No one wants to risk a repeat of those haunting consequences.
As in some other stories we will come to, the reason for selective management is the secrecy of the sea. Beneath the waves, all is hidden. If the waters were peeled back from coastal north Scotland and the hundreds of thousands of large seals were made visible, attitudes might change. The fish would look miniature and vulnerable by comparison, their attackers gross and greedy. But we see what we see, and what we see, we believe.
Seals have trouble catching fast-moving salmon in open seas, but weakened by reproduction and their starvation in freshwater the post-coital ghosts drifting from river-mouths make easy pickings in late winter. Early spring salmon in colder waters move slower, and they are easier prey too.
A few salmon survive. No one knows what predestines these few fish to survive their ordeals, but they do. Maybe they are just the fortunate ones. Many species cling to existence with only small numbers of breeders. They say the fecund rabbit can breed a million descendants in its own lifetime. Adult ‘hen’ salmon produce some 800 eggs for each pound of their body weight, so a good fish of fifteen pounds would squirt from her quivering flanks into the redds some 12,000 eggs. If she beat the odds and returned to spawn twice, she might have grown and be able to produce more eggs the second time. The egg output, though, depends on seasonal and physical factors and can vary widely.
The most times any salmon returned that I have heard of was a fish that negotiated survival for eight re-runs, which was netted off Newfoundland and aged by scale-reading – a cross-cut scale being interpreted like the rings of a tree. This one must have been up near the rabbit in terms of prolific genetic legacy! Similar return rates have been recorded in some of the glorious rivers of New Brunswick. On the eastern side of the Atlantic, a fish analysed in Wales had returned to the redds five times.
It is in the northern oceans that depleted salmon rebuild their condition. If you were to catch and eat these salmon before they had reconstituted themselves, they would be oily and disagreeable, like cod or mackerel after spawning.
For a long time pundits tried to work out where salmon winter; it was akin to the mystical quest for the end of the rainbow. Somewhere a fish as long as your finger grew exponentially to become a fish as long as your arm. Where was this fabulous larder? It is known now that a proportion of British salmon winter off western Greenland, where Greenlanders in small boats net them close to the coast. These salmon stay more than one winter. They are a minority here; many larger salmon from North America fatten off Greenland too. A little further north, the salmon of the Russian Kola Peninsular and the salmon connected to rivers on Norway’s long coastline winter in the North Atlantic off Norway.
The salmon of eastern North America winter in the Labrador Sea and on the northern Grand Banks, as well as western Greenland. It can be overlooked: the distance across the Davis Strait starting from northern Newfoundland is only 600 miles. Greenland’s seas are a neighbourhood bouillabaisse. The fact of highly variable runs of east-coast salmon in North America is reckoned by scientists to be related to the environment, food supply and ocean temperature; so much is reasonably obvious. But unlike on the eastern side, where salmon-run prediction is not attempted, Canadian and American forecasts on fish runs are based on what is found in the sea off Newfoundland and Labrador when the water reaches four degrees. In the 1980s and 1990s, between Labrador and western Greenland sea temperatures were suppressed by Arctic waters pushing south. This in turn saw declining growth rates across species like capelin and cod, delayed spawning times and generally reduced salmon runs.
Not only are weather and climate unpredictable variables at sea, but living matter in the sea is infinitely complex. Any child at the seaside has noticed that if you bottle seawater the life seems to fade away. This is because the sea is a dynamic environment in a state of continuing flux. Filled with plankton, microscopic living particles of plants and animals, the sea is a bubbling broth. It has been calculated that the amount of organic material in an acre of sea equates to the vegetation on an acre of average land. Planktonic abundance fuels the vitality of seawater and is the foundation for a pyramid of creatures feeding from one predator level to the next.
Adult salmon are near the top of this pyramid. Fast swimmers, they evade other fish. Vulnerable to being cornered by seals and acrobatic sea mammals when in semi-confined areas like estuaries, they are generally too swift for capture. The rich soup of planktonic life becomes in turn the feed for krill, capelin, herring, shrimps and molluscs, which are all part of salmon’s ocean diet.
Important elements like phosphorus and nitrogen determine marine productivity. These either wash onto the shelves that are the underwater extensions of landmasses, or are pushed from below in the deep ocean by upwellings as ocean currents mix, driven by the Earth’s rotation. Areas of the ocean vary enormously in their productivity, the North Sea and the Grand Banks being shallow expanses and exceptionally fertile, as contrasted to vast parts of the mid-Pacific where the water, as you peer into it with the sun behind, is startlingly clear precisely because there is so little plankton and suspended material. It is as void as sterilised bottled drinking water. In other places millions of plant cells can occupy one cubic foot of seawater.
This partially explains what has been called the ‘explosive growth’ which salmon display after leaving their freshwater nurseries as six-inch smolts.
Marine biology and marine research have made quantum leaps in recent time. Two areas of rapidly advancing research concern life in the bathymetric deeps, where life-forms have been discovered way below depths at which it was formerly thought any life at all could exist, and secondly in the pelagic or surface skin of the ocean. Although we now know that salmon obtain food from depths of as much as 800 metres in the dimmed realms of the sperm whale, and can stay at 400–600 metres for as long as 24 hours, it is in the surface ocean layer that smolts have to survive when they leave rivers.
Their departure is called the smolt ‘run’. The small fish leave their natal river for the great unknown when prompted by rising temperature. A government fisheries department in Scotland used infra-red images at night on a tributary of the River North Esk to watch smolts assembling for the ‘run’. The technology was not perfect; rising water levels lost the images of fish, but the presence of smolt-traps further downriver showed that smolts did indeed continue running in high waters. For the bigger picture the technology served adequately. It showed that fish shoaled in small parties of three to six, they used the core of the current for propulsion, and they descended rivers pointing seaward.
Tagging with microchips has established another new finding. Smolts enter the sea in a mass to minimise predation. Having travelled downriver in small schools, they pack to go to sea, then closer to the sea becomes an assembly point. The reason is the same as why other small fish shoal – it enhances an individual’s survival chance to be one of many congregated in a dense mass.
A salmon river is occasionally blessed with egg-bearing gravels all the way up its sinuous length. The Miramichi in Canada is an example of a spawning bed over a hundred miles long. Hen fish will sweep out redds and lay their eggs in them from the narrowest streams at the top to the wide, gravelly wash-out bars near the river-mouth. To coordinate the smolt runs, however, the development of eggs into fry and parr and then into smolts in the headwaters of the river must be earlier in the season, so that when these young shoals of salmon go seawards they do not miss the camouflage of other shoals of smolts which have matured later and which are waiting nearer the river-mouth.
Accordingly, in northern Scottish rivers parr begin to go silvery, and turn into smolts or ‘smoltify’, as early as March in the headwaters and as late as May lower down. To prepare them for ocean life, away from the shady corners and dark shadows of natal streams, they develop an ocean livery. Their skin grows a layer of silver guanine crystals. These crystals arranged in verticals rows act as mirrors, camouflaging the little fish by reflecting its surroundings.
The keen perception of Dr Richard Shelton, formerly head of the government’s marine laboratory in Pitlochry in Scotland, noted that the only parts of the smolt to remain unaltered are the black edges to the fin and tail. He believes these are helpful visual aids to other smolts in keeping the pack together, whilst not giving too much definition away to predators.
To help the smolt register where it originated, and to find its own personal natal stream later as a fully grown fish, the hormone thyroxine is raised temporarily to allow the small brain to take in vital extra survival information.
The cohort of smolts journeys down the river, making the little flips and splashes familiar to springtime anglers, and reaches the sea to coincide with feeding opportunities. The oldest smolts reach the salt first and the youngest, maybe only a year old, go last, an order which is reversed when they return as adults. A critical feeding assignation is with the outburst of sand-eel larvae on the sandbanks.
The similar appearance of different smolts is deceptive. Those from the southern edge of range, France and Spain, are a fraction of the age of individuals from colder northern rivers. Whereas many southern European smolts are just over a year old, those from Arctic Norway, Greenland and Ungava Bay may be seven before they risk life at sea. From Iceland and Scotland smolts have dwelt from between two and five years in the river. The age difference reflects the length of the growing season, further north, less time.
It is an extraordinary thought that physically similar fish, at the same development stage, vary in age by so much. There are no obvious parallels in bird or mammal biology. Possibly there are comparable patterns in other fish, but none comes to mind. Salmon evolution is supreme adaptation.
What happens after the entry into seawater has recently been tracked in an internationally funded programme codenamed SALSEA-Merge. SALSEA is the most remarkable research on a fish at sea in recent time. The European Union, Canada, the USA, the Total Foundation in France, the Atlantic Salmon Trust in the UK and a variety of universities and agencies combined to fit out the RV Celtic Voyager and two other vessels with proper equipment, and then put the right people on board who knew what questions to ask and how to get answers.
The results fill in another corner of the lifestyle jigsaw.
The research boats spent three years catching around 27,000 juvenile salmon from 466 different locations in the North Sea, the Norwegian and Irish seas, and generally in the north-east Atlantic around the Faroe Islands and Iceland. Information from 284 out of Europe’s 1,700 salmon rivers from nine countries was used in genetic sampling and analysis. The biggest sample came from Scotland, followed by Norway. By targeting the most productive and the largest rivers, the SALSEA team reckons that 80 per cent of Europe’s productive salmon area was embraced by the research effort. The resulting picture then is a clear story about European salmon, including Russia and Scandinavia, up to 2011.
The novel side of the analysis was the use of genetics. Only recent science allows researchers to find out where a fish comes from. Work on Ireland’s River Moy had already shown what a sprinkling of other rivers had found too – that inside their catchments salmon stocks can be divided up into genetically discrete populations. It was true of a minority of rivers, but demonstrated the impressive complexity of salmon adaptation.
The Atlantic salmon in some form or other has been occupying European and North American rivers for 60 million years. In that immense time it has developed local strains to adapt to local conditions. Then the last Ice Age ended, with a thaw that peeled back the ice-covered land over all Britain north of London. A mere 15,000 years separates us from the frigid conditions that dominated before. In cosmic terms it is a blink in time. Salmon saw pristine territory opening up in front of them, and occupied it.
Rivers in Scotland have plenty in common with other rivers in salmon range. They are spring-fed. These springs can come from hundreds of feet below ground and each one has a differing chemical composition. Also, the springs bubble from the ground loaded with different temperature readings, dependent on their depth.
Variations between springs account for differing populations of salmon. For the scent in each stream, and the mineral contents, differs from that of its neighbour. Salmon have brilliant olfactory senses, being able to pick out the most dilute odours from home-stream chemistry even through a fog of additives and man-made complexities. The fish’s ancestors have used that water and over time adapted to it.
Sometimes that adaptation will translate into an identifiable genetic type. SALSEA went to sea armed in advance with the genetic map of many rivers. The researchers were hunting smolts, young salmon entering an alien saltwater world pregnant with feeding and with threat. What galvanised researchers to go to all this effort? The answer to that question is both simple and complex. At the simple level, it is because the salmon is important enough to justify it – it is a glittering symbol of environmental wellbeing. The complex answer backtracks in time.
In the 1960s European rivers had seen prodigious runs of salmon. The silver bonanza from the spring tides re-ran the programme of fresh shoals arriving through the year and it seemed as certain as the sun dropping in the west that from the start of spring these great leaping, wild, sparkling fish would go on and on revitalising rivers which had gone doggo for the winter.
Then a decline commenced. Fewer and fewer salmon came back in the 1980s, and then the 1990s. The canaries in the mine, or anglers, found their enticing presentations drifting across the stream undisturbed. Nothing jumped. Nothing swirled at the fly. The waters rolled to sea unruffled. The rivers missed their most dramatic occupant.
A few rivers had installed fish counters, usually consisting of electronic beams broken by an upstream-swimming fish, and these counters, logged by computer, were telling an alarming story which backed up the anglers’ perceptions of fewer silver visitors.
It was estimated that in the 1960s and 1970s the population of salmon in the eastern Atlantic was around eight to ten million fish. In America and Canada, where many rivers had been dammed, where forest clearance in river-country had silted up river-beds and traumatised ecosystems, there is another story of dwindling fish, but we will revisit that side of the tale later.
The decline from abundance was giving rise to serious worry.
In places where smolt survival was being measured, such as at Scotland’s North Esk government monitoring station, and the Bush and Burrishoole system in Ireland, young sea-going smolts had once returned as salmon in numbers approaching 15 per cent of the outgoing migration. This figure was falling and falling steadily. It fell to eight and then as low as five per cent. On the River Conon in the northern Scottish Highlands, where they can measure these things, the return rate of smolts in 2011 was four per cent. In some rivers the number will be even less.
For anadromous fish, which live at sea and breed in freshwater rivers, this figure was low – very low. It told scientists that ocean-wide changes were occurring. Somewhere out there a black hole was consuming the small silver fish that used to fatten in the larder of the north-east Atlantic, before returning to their birthplaces in the pebbly streams. In some American rivers spawning pairs were down to a handful of pairs, a chilling brush with death equal to a doomed scenario.
The most obvious subtractions from salmon runs were then looked at and addressed. Salmon netting, which was recorded as having been prosecuted in some parts of the UK and Europe since the twelfth century, was an obvious target. Here was an industrial-scale subtraction, taking fish before they could breed. Furthermore, it violated one of the tenets of modern fisheries management – that you must know what stock of fish you are taking.
Netsmen took salmon offshore as they migrated past. No one had a clear idea which rivers they were due to swim into. A salmon in the net was a salmon in the net; they all looked much the same. They fetched the same price, too. Logic demanded that random salmon capture cease. On the back of the idea that netting was ‘indiscriminate’, harvesting individuals valuable to species survival alongside those from more numerous components of the migration, appeals were launched to save salmon by buying out or leasing netting stations. Many were laid off and mothballed and bought out. In Scotland alone the catch by nets was ratcheted down from around 100,000 salmon a year in 1990 to 13,000 twenty years later.
Salmon netting still exists in a few places in 2013. Norway remains unreconstructed about salmon netting. Scotland has a handful of active netting-stations, resistant to being bought off and encouraged by rising wild salmon prices, England even fewer. The Norwegian Saami people from the far north, with precious little to sustain them, still net salmon on the Arctic coast. In a conservation milestone for salmon, Iceland terminated netting at sea as far back as 1932. Pressed by the European Union, the west-coast Irish drift nets were outlawed in 2007.
The most important salmon-netting haul in modern times was taken off Greenland. It commenced in 1959 when gill-netters working the fjords were startled to find glittering salmon in the mesh. A boom in salmon commenced, which pulled in drift-net fishers close to Greenland’s western shore from Denmark, the Faroes and Norway. The working season was August to October, with the winter iced over. Catches rocketed, peaking at 2,689 tons in 1971. All of a sudden salmon, which are a rare fish in the sea, were being caught like mother cod, which can lay millions of eggs. The International Council for the Exploration of the Sea (ICES) reckoned the Greenland operation in winter 1972 had removed a third of all the salmon locally present. As more attention was paid to what exactly was being caught the fish were traced to the east coast of America and Canada and, secondly, older female salmon from Scotland.
