Anglers know them as the energetic little fellows that can seize a fly, sometimes almost of their own size, equally in fast riffles or at the tail of the pool in torpid backwaters. We dislike holding them for fear our hands are too hot, so we customarily let them wiggle free from the hook, holding them near the surface to skip off as they hit water.
Just as seagulls are a sign of worms being turned by the plough, so mergansers are a sign of parr shoals. On the famed Restigouche River in New Brunswick, where some of the largest Atlantic salmon abide, flocks of mergansers number hundreds. They fly in menacing sinister squadrons up and down the fish-rich river, making a commotion when they all settle. In the Fifties it was found on the nearby Miramichi River that 86 per cent of the local mergansers ate parr to the tune of over a million each annually! It almost defies belief, but tests elsewhere replicate a gargantuan consumption rate. Mergansers can decimate a salmon population, faster when the water is low. Restigouche kingfishers target parr too and in times past the fishery owners painstakingly shot both mergansers and kingfishers as part of routine salmon protection.
It is perhaps one of the oddest adaptations of Atlantic salmon that some of these miniature parr can be sexually mature. As we have seen, they are capable of fertilising big hen salmon on the redds, nipping in as the cocks pause and ejecting their little sprays of milt over them. Looked at from an evolutionary point of view it completes a portrait of salmon’s variable ways of circumventing catastrophe. If all the cock fish in the sea were boiled in the lava outflow of an erupting volcano (to take a fantastic scenario), then the female fish reaching home would not be reproductively marooned. That little barred parr would be waiting, successful fugitive from kingfishers, to secure the future of one more generation of fine salmon.
Parr feed on the full range of titbits that the meagre headwaters of salmon rivers have to offer. Mayflies, stoneflies, other insects and insect larvae, worms and mussels – most things moving and many unmoving contribute to diet. Vulnerable to acidification and very low levels of pH, to chemical discharges from agricultural crops like silage, concentrated effluents, mining tailings, high aluminium and heavy metals, wood dust, oils and the like, parr need clear water and flowing streams. A simple-sounding requirement, but in a land-hungry world clean water is not such a common commodity. As they prepare to ‘smoltify’, their tails lengthen and the forks in them deepen, their fins grow, the scales soften, and they turn silvery. The great odyssey in the ocean is about to commence.
It is a matter of wonder that such small creatures can be destined to go so far. When birds migrate, they are of a similar size to their progenitors. When flounders and shad and lampreys shift in and out of the salt water on the tides they cover measurable distance on a manageable scale. Other mammal migrants travel in families and herds, adults protecting young. Caribou and elephants and migrating African antelope shepherd their young, fending off predators on their behalf. But these small salmon are unaccompanied minors, with a threat-filled odyssey ahead. On the trip they rub shoulders with whales, they are tossed and turned in the ocean’s systems, upwellings and currents and still they adhere to their programmed track. SALSEA identifies the routes and genetic families of some of the journeymen.
When common eels leave the Sargasso as elvers they allow the prevailing winds and currents to push them across the Atlantic towards freshwater lakes. The journey can take years, but the fish are essentially passive. It is the determinism of the young salmon that amazes. Predestined to reach a feeding ground, whether in the North Sea as grilse, or on the Greenland Shelf and north-east Atlantic as multi-sea-winter salmon, they are on a mission, bent on their assignation with copious krill and capelin and other nutritious sweetmeats. The whole challenge is formidable in the extreme.
I was in a party of river rafters on the Alaskan panhandle late one summer and we had finished taking apart our gear and were waiting to be picked up. We dawdled around a river-mouth where a multitude of salmon were swarming. Biologists had blocked the small river-mouth with a grid because enough spawners were already jammed in the river and more would overload the small rivers where they bred. Families with open pick-ups were backing onto the edge of the pool and the men were snow-shovelling palpitating salmon directly into the backs of the pick-ups. They filled the rear of their vehicles, pulled tarpaulins over the still-thrashing salmon and drove off. Winter food supply all sorted.
These biblical-scale salmon runs are not all gone. In fact, they continue. It was a year predicted by fishery scientists as likely to be low on spawners, and a multitude arrived.
The world of antediluvian excess, of passenger pigeons in numbers to darken the sky, of fish which break nets and pull trawlers under the waves, of buffalo whose thundering hooves made the American plains shake from far away, these examples of Nature’s gargantuan excess still exist in parts of the Pacific salmon domain. It is reckoned that in the southern edge of range, America’s Washington State and Oregon, only a tenth of the original runs survive, but north of that runs persist.
What is unknown is the degree to which hatchery efforts by Alaskan fish and game managers are reinforcing migrations. Only genetic testing from the annual runs, against a database of the genetics of salmon used in the hatcheries, would show this, and the record was not taken. There is an element of hybridisation in the run.
I was shown a tributary of the Campbell River on Vancouver Island where pink salmon waiting to spawn were stacked like sardines in a tin. The place was dense with vegetation and only as the fishing guide pushed aside the tree branches did I make out what was in the water. It was like looking into a wine rack where the bottle heads were fish faces. Having spent over a week seeking one lonely steelhead willing to engage with my fly patterns it was a trifle galling to see a stack of fish so dense it pushed water from the river onto the bank.
In July 2010 I was in Vancouver when the sockeye were thronging the bays around the city. Rod fishers were all over, filling larders for winter. There was some edgy banter, too, about whether these super-abundant fish should be returned or not. Conservation talk about perilously damaged fish-runs, even of a different salmon species, had altered public perceptions. The language of conservation and the more acute sense that wildlife values must from now on be looked after has hyped issues, and common sense can get lost. One species gets muddled with another in the public eye and the projection of fishermen as ruthless, greedy hunter-gatherers becomes lodged in the public mind.
Long ago in the history of fish management in western American and Canadian culture it was hard to make the case for the protection of migratory fisheries against the socio-economic advantages of industrial advance, timber-logging, and the power of hydro-energy. Nowadays, in instances of survival adequacy it is sometimes hard to make the case for a controlled take.
The point about the prodigious runs of salmon into western Pacific rivers is more significant, though. The salmon runs dictated human settlement; this can be shown compellingly. No one has applied this information to settlement history in Western Europe. Here the Atlantic salmon, not the Pacific species, was the bonanza of protein delivered by migratory evolution. It is known that the Phoenicians netted tuna in the open sea two thousand years ago. Anyone capable of doing that, and capturing very large fish which were also the fastest swimmers in the sea, could with comparatively little effort have trapped salmon. And they did.
Take the Pacific coast first. In his 2011 book comparing the New World and the Old World, entitled The Great Divide, Peter Watson examines the effects of a great climate shift. From around 6000 BC sea levels began to stabilise. Glaciers had been pouring fresh water into the seas, and land had been rising as the weight of ice lifted. This process eventually levelled out. Vast shoals of salmon began to swim up the pristine rivers. A harvest of fish arrived on the doorstep of tribes on river-mouths and it came every year, regular as the turning season.
Peter