It happens every four years, an enthralling natural spectacle that scientists cannot fully explain. Three weeks ago more than two million sockeye salmon left the Pacific Ocean and began their arduous 330-mile odyssey upstream to spawn in the gravel beds of the Adams River in south-central
British Columbia. During the 18-day journey the fish stop eating. As well, their bodies change color from silver to a brilliant scarlet, and their heads become dark green. At the spawning grounds, the females lay eggs which are fertilized by courting males. Then, within hours, the mature salmon die. This year about 225,000 tourists and nature lovers gathered by the Adams from as far away as Europe and Japan to witness the salmon run. “This is the biggest wildlife event in North America,” said Christopher Harris, a senior naturalist for British Columbia’s provincial parks. “It is like a good movie—it has sex, violence, color and big numbers.” The Adams salmon run is the larg-
est phenomenon of its type in the world. This year’s has involved the most salmon since 1958, when an estimated four million fish returned to the spawning grounds. Naturalists predict that the current spawning could produce one billion sockeye offspring, known as fry. But over the next four years, less than one per cent of them will survive natural predators and commercial fishermen to undertake the river run themselves.
While the salmon ran and the spawning took place, tourists strolled quietly along banks of the river, many of them awestruck. Said Rusty Welshon, 29, of Boulder, Colo., who travelled 3,000 km by car to see the sockeye: “The whole life cycle is just spread out there before your eyes. It’s incredible.” Although it remains largely a mystery how— and why—salmon return to their spawning grounds, there is evidence that a keen sense of smell helps them find the place where they were born. In any event, once they locate the upper reaches of the Adams River they are in an excellent spawning ground, with pure water from icy streams, little sediment and fine gravel beds to receive the eggs. Indeed, the federal fisheries officials and B.C. park agents are committed to preserving the habitat, which is 75 km east of Kamloops. In recent years the province has purchased private land holdings along the river to prevent unwelcome development. Said Harris: “We got this area put aside in the late 1970s, when there was talk of putting in a subdivision. The land base is now protected, but there are still things like river pollution that can affect the stocks.” Still, he says that he is confident that some of this year’s fry will return in four years. And once again thousands of onlookers will gather for a life-and-death drama of a species reproducing itself.
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