Pacific Northwest salmon populations shift dramatically

As Vancouver, B.C., watches Fraser River stocks of sockeye fail, the count of steelhead passing the Bonneville Dam in Vancouver, Wash., is soaring. And while low Alaskan Yukon runs of king and chum salmon predict a devastating winter for subsistence fishermen, salmon are even making a comeback in the Seine, as InvestigateWest reported last week. What differences could account for these drastic population changes?

Multiple environmental factors could be affecting populations. Warmer weather can heat up rivers, especially those overdrawn by humans, and discourage the cold-water-loving fish from heading upstream. Shifting ocean currents or other predator influences could be altering food sources. Pollutants from stormwater can accumulate in the fish. Overfishing can deplete numbers. Sea lice from farmed salmon could be transferring to wild salmon, weakening them and increasing the likelihood of succumbing to disease or predators. Even superb returns from previous years could be problematic, as too many fish spawning and then decomposing could produce excess bacteria, possibly resulting in disease.

Or the culprit could be politics. Alaska's Taku River is downstream from a British Columbian mine, but the river's status as important habitat for 2 million salmon prompted protection for the entire U.S. section of the river. The Alaska Department of Fish & Game works with the Canadian Department of Fisheries and Oceans and the Taku River Tlingit First Nation to preserve fish stocks for multiple parties and uses, and salmon populations there are stable. Even Sarah Palin pushed for mine waste reduction and management of the river before stepping down as governor.

Groups like the Living Oceans Society in B.C. are working with communities and government organizations to develop integrated coastal management areas. Other areas in the Pacific Northwest are testing new fishery management techniques with tagging programs and habitat reconstruction. So are areas like the Fraser River suffering from pollution and other environmental issues, or simply not enough political action?

Regardless of cause, the massive population changes spell disaster for subsistence fishermen in Alaska and Canada. Millions of people live in the Fraser Basin and near other Pacific Northwest rivers, and it is difficult to sustainably balance human populations and resources. Salmon obey biological instincts rather than political divisions and environmental regulations. If we don't work collectively to manage their habitat, important runs of this iconic Western fish could disappear.

– Emily Linroth