Salmon in the pines
Every fall hundreds of kokanee salmon spawn in the rocky shallows of Idaho’s Lake Coeur d’Alene, and each fall tons of of bald eagles descend to devour them. One frigid, blustery day in early January, Elise and I drove out to catch the tail finish of the months-long feast. The eagle flock had been smaller this 12 months than in the latest previous, and departed early; by the time we arrived, solely 4 or 5 nonetheless lingered at Higgins Point. The raptors hovered in the stiff gusts like kites and perched miserably in the shuddering ponderosas, so fluffed towards the chilly they might have handed for birbs.
The kokanee run had lengthy since wrapped up, too, although, not like the migratory eagles, the salmon wouldn’t be departing Lake Coeur d’Alene at journey’s finish. Hundreds of spawned-out carcasses lay at the wrack line, decrepit our bodies so densely piled that, upon first blush, they had been indistinguishable from the cobble. The fish weren’t mendacity on the seaside; they had been the seaside. Our canine, Kit, tried to roll in the sludge, displaying her species’ unerring intuition for doing the most disgusting potential factor in any given second.
We dragged Kit away and adopted a path uphill, into the cowl of the pines. The salmon appeared to comply with. Even tons of of ft from the lake, their corpses littered the forest flooring, staring blindly at us from pecked-out sockets. Needle tooth lined their jaws, which had been transfigured by the spawn into hooked, leering kypes. Some kokanee had chunks lacking from their ragged backs; some had been solely heads. They had been most concentrated, I observed, at the base of the eagles’ perch bushes. Quite clearly, they’d been dropped.
Salmon, after all, are nature’s most good nutrient packages. At sea, they convert bountiful sources into flesh, then — generously, graciously, as if paying tribute to the river that parented them — convey nitrogen upstream in their failing tissues. They carry out the incalculable service of dying, their sacrifice paid ahead by the bears and otters and osprey that scatter their bones all through coastal forests. Trees alongside salmon streams, analysis has confirmed, develop sooner than their fishless counterparts, enriched by the present of pores and skin and guts.
Although I’d seen (and caught) spawning salmon earlier than, I’d by no means witnessed the “salmon in the trees” idea illustrated as neatly because it was at Lake Coeur d’Alene. The fish lay in the pine needles in numerous levels of putrefaction,dissolving slowly again into the earth, their meat puddled and melting like ice cream on a summer time day.Stuffed bald eagles, so flush with dying fish they couldn’t be bothered to retrieve the meals they dropped, had inadvertently fertilized their very own ponderosa grove.
Yet the state of affairs at Higgins Point deviated from the basic story in a few respects. First, and most clearly, Lake Coeur d’Alene is, duh, a lake, and thus presumably much less nutrient-rich than the ocean. (The kokanee, which is the sockeye salmon’s landlocked kind, is far smaller than its species’ marine model exactly because of this.) To my information, all the research on salmon’s extraordinary fertilization powers have been performed alongside streams that drain to the ocean. Are salmon nitrogenous sufficient to generate the similar advantages even once they’ve spent their lives in the relative poverty of freshwater?
(This is just not a rhetorical query — if you realize the reply, or not less than care to have interaction in some knowledgeable hypothesis, please remark!)
Even extra intriguing is the indisputable fact that, a century in the past, a customer to Lake Coeur d’Alene wouldn’t have trod upon even a single useless kokanee. That’s as a result of the fish aren’t native to the lake, having been launched by the Idaho Department of Fish & Game in the 1930s as cannon fodder for anglers. (The choice was motivated in half by historic mining air pollution, which so fouled the Coeur d’Alene River that the watershed’s native cutthroat trout collapsed; apparently it was less complicated to launch an entire new fish species than clear the place up.) Eagles, in their magical, mysterious method, finally recognized this anthropogenic meals supply and commenced gathering in North Idaho en mass. By 1974, they had been so entrenched that the Bureau of Land Management started annual counts, which have continued to this present day. Together, a non-native fish and North America’s most iconic avian predator had conspired to delivery a novel ecosystem.
As we drove house — the wind whipping up chop on the lake behind us, the canine radiating a faint whiff of seafood market from the backseat — I mulled the questions raised by this fascinating ecological dynamic. How does fertilization from landlocked salmon examine to marine fish? Could a biologist with a recognizing scope observe the nitrogen contributions of particular person eagles, as if they’re level sources? Can you detect the date of kokanee introduction in tree rings? This place is a gold mine for enterprising masters college students, I’m satisfied — why threat grizzly bear assault and mosquito exsanguination in the Alaskan bush when you might examine the similar phenomenon in the resort city the place Kim and Kanye spend their summers?
It’s a reminder, too, of how poorly we perceive the world we’ve formed; the lasting biochemical and ecological penalties of our forebears’ choices; and the ecosystem engineers round us, all the time and in every single place, changing flesh to soil to wooden and again once more, biking by means of time and area in the scales of a fish, the feathers of an eagle, the ochre jigsaw bark of a ponderosa pine.