The Salmon: The Extraordinary Story of the King of Fish. Michael Wigan

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СКАЧАТЬ heads at male parr trying to get near the females on the redds, but a knob this solid is hardly needed for that. As big cocks charge and chase each other the kype may be a proboscis for belabouring rivals. When the cock reassembles his hormones after spawning and drifts downriver as a kelt, the kype in sympathy shrinks too, till only the familiar small hook is left. Unless this happened he could never resume feeding.

      The cock’s head attains super-gothic ferocity, being elongated for the spawning by three or four inches, and his skin blackens. At the finale he hardly looks like a fish at all.

      When at our local hatchery we had schoolchildren on an afternoon out acquainting themselves with the species for the first time, I remember a fishery bailiff hauling a cock salmon from a deep holding tank and the wide-eyed, disgusting-looking monster squirming from side to side, eliciting a gasp of horror from the young onlookers who jumped backwards. They may have seen some X-rated movies, but this was something else.

      Normally, after 50–110 days, the incubation extending to eight months in the colder Arctic, the salmon eggs break forth as tadpole-like creatures, carting as an underbelly appendage the vital egg sac. This bulging picnic is for consumption on the next stage of the pilgrimage, before they can start feeding from the outer world for themselves. As the little jelly-like creature, with its sharp, black, instantly functioning eyes expands, the picnic shrinks, and after six to eight weeks has been completely absorbed. From that time, life support is externally supplied – or existence ends.

      Fry, as they are called, eat tiny crustaceans, insect larvae, nymphs and phytoplankton – a variety of miniature organisms that flourish in stream sunlight. They subsist on their hunting skills, which are rapidly developed. In summer heat food multiplies and in winter it shrinks till it disappears, their growth mirroring food availability. The further they range from the safety of shade and cover, the higher the risk of ending up in the stomach of a trout, heron, kingfisher, cormorant, or other assailant. In the fecund backwaters of Scotland’s Aberdeenshire River Deveron, where the water is clear and glassy, I have seen thousands of fry massed in corners. The fugitive instincts they need in later life are in evidence early and they move like lightning, even from passing shadows.

      The parr stage is marked when they reach a couple of inches. Parr have snub noses, brownish backs, some black spotting, and a few red spots near the lateral line. This line is their nerve system, the strung-out headquarters where their sensory faculties are assembled. Parr have an easy signature in several dark bands running vertically up and down the body, no sign of which survives beyond this stage of their existence. The barring accounts for the term sometimes used to describe them: ‘fingerlings’.

      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.

The Culture

      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, СКАЧАТЬ