It's not easy being a Pacific salmon. You get just one shot at procreation--and then you die. And you can't have your last hurrah just anywhere. You've got to travel back to the exact place you were born--an upstream journey that can approach 1,000 miles in length and 6,000 feet in elevation. Along the way, you're easy pickings for the eagles, bears, and anglers that consider you a singular delicacy. This life of adversity is what nature and evolution have devised for you. Add to it the stresses of the human world--dams, commercial fishing, irrigation--and you are, it would seem, a hapless fish with a tough future.
What the salmon does possess, however, is an integral place in the culture and heritage of the Pacific Northwest. This cultural significance, along with its commercial importance, means that many people, with many divergent interests, are willing to work together to brighten the Pacific salmon's future. From hydropower to hatcheries, all sides agree: the salmon must be saved. The Desert Research Institute's Dr. Kelly Redmond, Regional Climatologist and Deputy Director of the Western Regional Climate Center, is one of those people interested in helping. Along with Dr. Roger Pulwarty of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder, Redmond has completed a study looking at the role of climate and climate-related information in the management and recovery of the salmon population in the Columbia River basin. The study was published in the March 1997 edition of the Bulletin of the American Meteorological Society.
And there is certainly some recovering to be done. "There were probably 11 to 16 million wild salmon in the Columbia River system before the first Europeans arrived here," says Redmond. "Today, estimates are somewhere around 300,000 to 1 million wild salmon." Everyone agrees that human activities are largely responsible for this dramatic decline. The Pacific Northwest has become dependent on the Columbia River system for power production, irrigation, navigation, flood control, and water supplies. The basin now has about 250 dams that provide electricity at 60% of the national average price to millions of consumers in Washington and Oregon. But the dams that make this cheap power possible also impede the unique life cycle of the Pacific salmon. It is difficult--with dozens of man-made obstacles in your path--to swim upstream to spawn or, as a baby salmon, to float downstream to the ocean. Fish ladders, spillways, and elaborate shunting devices are all used to help the salmon past these concrete barriers, but a large toll is still taken each year.
And dams are not the only obstacle. Habitat degradation from development as well as stream siltation from logging and grazing reduce the viability of the eggs and young fish. Hatcheries established to increase populations and aid commercial fishing operations have instead had a negative effect on the native stock by increasing competition and introducing disease and less genetically robust fish. And commercial fisheries, as important parts of the region's economy, continue to harvest fish despite the declining numbers.
But as Redmond's study points out, we can't accurately judge the harm done by these factors without considering, and attempting to understand, the mechanisms behind the salmon population's natural fluctuations. And a significant reason for those natural fluctuations is climate.
"To assess whether mitigating actions are helpful, we really have to know what would have happened if we had done nothing at all," says Redmond. "If we don't incorporate what we know about climate behavior and its effect on the fish, we may end up making less well informed and less effective decisions about management."
Climate is an important backdrop to the Pacific salmon's situation and can affect the fish differently during various stages of its life. Temperature is important, since salmon eggs need cold, clean water in which to hatch. Warm water and heavy sedimentation invite disease. Snow and rainfall rates directly affect another important variable for the salmon--water levels. Low water levels hamper the progress of the salmon swimming upstream and reduce the surface area of river bottoms for egg laying. Slow moving streams also make the trip to the ocean take longer, increasing the danger for young fish. Unusually high, swift flowing rivers, on the other hand, tend to dislodge eggs before they hatch. As adults, salmon are also sensitive to changing ocean temperatures and wind-driven currents, which can affect the nutrient density of the waters.
But as Redmond and scientists like him gain a better understanding of how weather and climate affect the salmon, they are still faced with the age-old challenge of predicting the weather. "A good climate forecast is worth a lot of money in the Pacific Northwest," says Redmond. "Water managers would love to know what the winter will bring by August or September, so they could decide how to manage flow and reservoir levels. If we can bring them more accurate forecasts, they can make better decisions."
A major part of Pulwarty and Redmond's study involved finding out how (or even whether) those who manage the Columbia River system use climate information and what new roles and applications might be possible with recent advances in climate forecasting. They found that long-term forecasting of runoff, river transit times, and stream temperatures were primary needs in salmon management decisions. But, despite the significant influence of weather and precipitation rates on the problem, climate forecasts aren't being used.
"In this case, people are almost universally aware of the importance of climate on the salmon but do not use available operational climate forecasts to help them make decisions about their management." Redmond sees this as just another example of a problem inherent to much scientific work. "There's often a disconnect between when we as scientists make a discovery and when those who would benefit from that discovery get the information. To really benefit society, we need to understand not just our own scientific disciplines but also how our knowledge can be transferred to those who can use it."
Besides overcoming a reluctance to rely on information that is inherently uncertain, such as a climate forecast, there is also a need to show people how to interpret and apply climate information to a particular problem and to make that climate information more readily available and usable.
So, as power companies, recreationists, fishermen, and farmers vie for the precious resources of the Columbia River system, the Pacific salmon continues its mysterious life cycle, from stream to ocean and back again. "We are trying to find the best way to live side by side with this species, which we simultaneously admire and exploit," says Redmond. "However, this fish is swimming not just through the waters of the Columbia River system but also through some 70 different administrative jurisdictions, with a wide variety of interests.
Getting the actions of all those groups in sync and helping them make effective joint decisions may have as much to do with the salmon's preservation as anything else." In other words, as decision makers in the Pacific Northwest undertake what has become a huge, comprehensive attempt at ecosystem management, they may be learning as much about themselves as about the Pacific salmon.