My son and I splash upstream in hip boots, searching for signs of the sockeye salmon that return each summer to spawn and die in this wild Alaskan creek. I've come here to see for myself what he wrote home about last year:
The creek is so full of sockeye, it's a challenge just to walk upstream. I stumble and skid on dead salmon washed up on the gravel bars. It's like stepping on human legs. When I accidentally trip over a carcass, it moans, releasing trapped gas. In shallow water, fish slam into my boots. Spawned-out salmon, moldy and dying, drift down the current and nudge against my ankles. Glaucous-winged gulls swarm and scream upstream, a sign the grizzlies are fishing. The creek stinks of death.
Today the whole streamside world is clean and sparkling. We slosh along gravel bars, startling golden-crowned sparrows, until Jon bends down and picks up a single salmon vertebra, bleached white. Other than this, all evidence of salmon has disappeared.
Where did the piles of dead salmon he witnessed go? What difference does their living and dying make to the health of the entire ecosystem?
Jon, a graduate student in aquatic ecology, works summers with the Alaska Salmon Program of the University of Washington, a research project begun in 1946. The program's scientists and their colleagues in other institutions are finding that salmon, as they fatten in the ocean and then swim back into freshwater creeks and lakes, return energy and nutrients upriver in a vast recycling system that nourishes plant and animal life throughout the watershed. The nutrients leave a chemical record in lake bottoms that charts the rise and fall of salmon populations and may offer clues to patterns of climate change.
