The Pink and Chum Salmon that arrived a couple weeks ago are finishing their spawn and dying en-masse. Half-dead zombie fish, their flesh rotting as they swim, struggle to remain at their stations as programmed cell death shuts down the last of their functions. Rotting corpses litter the gravel bars. Contrary to what you may have learned, this is not the result of exhaustion. Other fish in this family (Steelhead, Atlantic Salmon, Arctic Char) make equal or longer migrations and live to spawn again. No. This kamikaze physiology is a beneficial adaptation, the result of evolution. Over many millennia, the offspring of fish that died after spawning had better survival rates because of the additional nutrients brought into the streams by the death of their parents the previous summer. For Pacific Salmon, which return to relatively infertile waters, this has proved a winning tactic and all five species have adopted it. A few King (Chinook) Salmon from this years dismal run can be seen here and there taking their last gasps. On rivers south of here that connect to lakes, the candy apple red Sockeye (Red Salmon) are going through the same process. Silver Salmon (Coho) are the last to arrive and are currently flooding in. The early birds are already starting to take on crimson spawning colors. Their meat is still good right now but theyll be the swimming dead by the time the leaves start to turn in early September. Summer here follows a tight schedule. Amid all this death and decay, the resident fauna enjoy a yearly smorgasbord. Black and brown bears munch the heads for fatty brain tissue and strip out the rich roe. The rest is left for gulls and ravens, who delight in eating the eyeballs first. Maggots break down what remains. The smell of the process, revolting to visitors from outside, is one Alaskan fishermen are fond of because of what it means is happening beneath the surface. Resident Rainbow Trout, Dolly Varden, and Arctic Grayling are lined up like diners at one of those conveyor belt sushi restaurants. The current now brings a constant stream of eggs and salmon flesh. They stuff themselves to the point of regurgitation and then eat some more. The few months of salmon bounty allows these fish to reach immense proportions despite fasting under ice for much of the year. Unlike salmon, which spend between two and four years growing quickly in a bountiful marine environment before committing mass suicide, these fish will live twenty or thirty years. Theyll spawn each year, eat salmon smolt, roe, flesh, and the occasional aquatic insect each summer, and finally succumb to predation or old age. Because of this longevity and the fragile nature of their populations, responsible anglers practice catch-and-release when pursuing trout, dollies, and grayling. We join them in dining on Salmon and share a kind of kinship. Especially with those individuals we catch year after year in the same stretch of river and come to recognize as both kindred souls and worthy opponents. Until about a century ago, salmon-centric ecosystems like Ive just described were ubiquitous along the entire west coast of the U.S. All the way down to San Diego. Most have been wiped out by dams, pollution, and overfishing. The scenes I have just described are now almost uniquely Alaskan. Worth remembering as our state government tries to convince us that its a good idea to install a hydroelectric dam on the Susitna River, of which this particular stream is a tributary.
Posted on: Fri, 15 Aug 2014 05:46:21 +0000