Название | The Salmon: The Extraordinary Story of the King of Fish |
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Автор произведения | Michael Wigan |
Жанр | Природа и животные |
Серия | |
Издательство | Природа и животные |
Год выпуска | 0 |
isbn | 9780007487653 |
No one who has read Haig-Brown’s account will feel brave enough to attempt their own description. His spare, detailed and probing simple language turns the enactment of egg-release into a pageant of wildlife drama. He describes the hen’s convulsing flanks as she releases eggs, redd-digging with fierce sweeps of her mighty tail, the water current helping the process. Then the arrival of the cock squirting his cloudy milt over the egg pile, the competing immature Chinook rushing in to have his go at contributing to procreation, prior to the whole nest being rapidly covered with pebbles in protection from the throng of potential predators needing just such a feast of fresh protein before the onset of north Canadian winter rigour.
At last he describes her dying, being eaten alive by rot, the fungus which softens and breaks down the flesh. Our heroine mother is left disintegrating on the stones. But, critically in Nature’s cycle, her dismembering body flakes feed vital protein to young fish and her distant successors. It is noble writing, and gripping. In stately style he takes longer over some passages of this enactment than the real-life duration.
To watch salmon spawning is an elevating experience available to anyone living in salmon country anywhere. Yet we are glued to wildlife films for their perfecting, high-tech, laboratory touching-up, editing and enhancing. Nothing can give you the smell of the real-life river at spawning, the proximity, and the clarity.
Usually between sundown and midnight, working upstream, the hen turns on her side and scoops a depression in a sandy and gravelly substratum, laying eggs all the while in a steady outpouring. The eggs remain fertile for only one minute, so contenders vie to fertilise them, squirting their cloudy milt. Action is furious. The redds are then covered over with the same stone-shovelling to a depth of up to a foot.
I saw this process one time on a gravel-bar below my house late in November after most fish had spawned. The salmon were same-sized, around 35 pounds. I had recently handled some big salmon and although fish of this size are seldom seen in the River Helmsdale, that was the class of fish I was watching. She lay just in front of him, but instead of a vigorous and exhausting performance these two were in languorous mode. They were so large that no grilse, parr or other contenders were visibly around. Their backs were clear of the water, and the two giants seemed just to nudge each other on the redd. I had two of my children with me and, riding piggy-back, they could see it all from a better height only a few yards across the stream. I almost felt like going away out of politeness.
Enquiring later about the presence of such leviathans, a retired fishery bailiff told me he had long known about these very big salmon. They entered this river after angling had finished, often not till November, and stayed only long enough to spawn. He reckoned they were usually no more than a fortnight in fresh water.
The salmon eggs are clustered in the redds until they hatch, safe from most eventualities except major flooding when rolling rock could smash their soft mounds and disperse the egg collection for consumption by all and sundry. For there are few denizens of salmon headwaters for whom fresh eggs are not a welcome dietary enhancement. Unlucky clutches too near the surface can be frozen solid on gravel-bars exposed to hard frost which has driven down water levels. Redds are safe if there is stability in the river system until they hatch in the spring.
The actors in the conception drama have changed their costumes to participate. Both sexes’ noses become extended. If he were a medieval knight trying to unnerve his jousting opponent, the features the cock salmon arraigns himself in might fit the bill. He grows a lower-jaw projection in the form of a solid gristle hook which curves up, sometimes actually piercing the cartilage of his upper mouth, which itself arches, pre-spawning, to accommodate it. The knob has a name, the ‘kype’, but its purpose is uncertain. Salmon fishery managers have seen cock salmon thrash their 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,