Scientists' views reveal disagreement, but often that generates knowledge

By Andy Duncan

With the salmon issue, why can't we simply turn to science for all the neat, tidy answers we need?

One reason is that some of the questions involve public choices, not just science. Another reason is that science isn't tidy. Scientists often disagree with one another.

"But we know a lot--enough to give informed advice and help the people of Oregon help the fish," says Jim Martin, an assistant director of the Oregon Department of Fish and Wildlife and a developer of the Oregon Plan for Salmon and Watersheds.

"Years ago," recalls Logan Norris, the head of Oregon State University's Department of Forest Science, "we [scientists] didn't fully understand the system salmon are a part of and told people to take the woody debris out of streams. It turns out we were wrong. Large woody debris like logs provides important habitat for salmon.

"People who expect perfection in human decision making are certain to be disappointed," Norris continues. "Almost certainly some things we conclude now will prove to be wrong years from now when more information is available. But in science the only way to avoid being wrong is to do nothing, and that's certainly wrong."

Martin uses a medical analogy. "We all know medical knowledge is imperfect," he says, 'but we usually take the doctor's advice."

Exactly how could scientists, with all their degrees and expertise, reach different conclusions?

In part, it's the process they use: observing, hypothesizing, testing, debating and validating. To fully understand something, they study it from different angles, or disciplines. And they're human. They look at the world through their life experiences.

"It is in the limelight of disagreement that new knowledge is developed," says Robert Beschta, a hydrology professor in the OSU College of Forestry who does salmon-related research.

The field of salmon science is broad. Let's look at some scientists' thoughts in a few areas. First of all, on what they call habitat:

Many biologists agree that a large amount of the salmon's inland home--forested and grass-covered uplands, and stream and streamside areas from headwaters to estuaries--has been degraded. Some a little, some a lot.

"This is a huge area of scientific consensus and we need to make decisions flowing out of that," asserts Bill Liss, a fisheries biologist at Oregon State University.

What caused the habitat problem, and how bad is it? In Oregon, the list of contributors to habitat degradation that scientists and others have identified leads to just about every resident of the state, as well as to natural processes.

The list of human-related factors includes: dams, many parts of urban and suburban life, fishing, forestry, farming, ranching, mining, manufacturing and many other kinds of industry. There's still some disagreement and uncertainty among scientists over the amount, and causes, of habitat problems in particular areas. The greatest debate is over the relative importance of each factor.

Another area where scientists' opinions vary is on how to fix salmon habitat problems.

"In my opinion, the first and most critical step is to halt or modify activities causing degradation or preventing recovery," says Beschta, the OSU hydrology researcher. "This is sometimes called passive restoration. It allows nature to do the job.

"Where such efforts are still insufficient for recovery to occur," he continues, "intervention by humans, sometimes called active restoration, may be needed to make streams better places for salmon to live."

A carefully timed combination approach may be best sometimes, and a long-term focus is always important, he adds.

Derek Godwin, a bioresources engineer, is a watershed extension specialist in Coos and Curry counties with the OSU Sea Grant, agriculture and forestry programs. Godwin works on restoration projects involving streams used by endangered coho and other salmon.

"I'm for active restoration," he says. "You should be encouraging Mother Nature along to where she would go anyway. With passive restoration, it will get there, but it may mean waiting 20 years or more. The landowners I work with often are willing to protect salmon habitat by keeping livestock out of the riparian [streamside] zone, or changing other ways they use the land. But they definitely like to be active in restoring the habitat, too."

"From my perspective, the active versus passive restoration debate depends a lot on what we think we know," says Dan Bottom, a research biologist with the Oregon Department of Fish and Wildlife. "We now know wood is important because we have a lot of data to show this. But we still do not have a lot of experience 'fixing' things in complex systems.

"We can put wood back in some locations and hope it recreates the functions we lost. We have some data to suggest this is possible, but nothing long term," adds Bottom. "While I agree we need to try some things, we also need to be cautious and not make a lot of local decisions that add up to large-scale mistakes. Passive restoration is a low-risk policy that requires time. Active restoration is much more costly, will be difficult to afford on large scales, but may be useful where passive processes will take too long by themselves."

Whether the restoration is passive or active, Bill Krueger, the head of Oregon State University's Department of Rangeland Resources, says he thinks organizations like watershed councils and Watershed Ecosystem Management (WESt), a program the Oregon Cattlemen's Association developed to help residents learn more about how to protect and improve their watersheds, "are on the right track. They get people thinking of salmon when they make decisions, and the decisions are site specific."

An area where quite a few fish biologists, and some other scientists, have similar views is on hatcheries. They say salmon produced as a "commodity" in many hatcheries in the past hurt wild salmon, competing with them for habitat and food and allowing salmon harvests that chipped away at shrinking populations of wild salmon.

"We swamped the wild fish with these hatchery fish for decades with the best intentions, thinking that was the right thing to do," says Jim Martin. "But rather than hand-wringing and blame-slinging, I think we should celebrate that we're finally smart enough to know that hatcheries, the way we ran them, hurt wild fish."

Not every scientist has a negative view of hatcheries. "The hatchery fish came from native fish. They have the genetic traits to be very adaptive. There are successful examples of restoration using hatchery-reared fish," says Henry Yuen, a fisheries biologist for the Columbia River Inter-Tribal Fish Commission, based in Portland. He notes that the hatchery fish used in restoration should be descendents of salmon that evolved in the area.

However, some people contend that restoration successes with hatchery-reared salmon have not been tested over an extended period of time (over decades, for example).

There's a major research need, according to Don Chapman, a fish biologist with a private consulting firm in Idaho.

"The elephant sitting in the front room," says Chapman, "is ocean ecology. There's a lack of understanding of that, even though many of these salmon species spend more than half their lives at sea. There's an awful lot about salmon in the ocean we don't know." That also makes it hard to calculate the impacts of inland problems more precisely, he says.

Like a lot of other scientists, Chapman believes a wide range of human activities and natural processes are responsible for the salmon decline.

"Dams are a problem on the Columbia River," he says, "but what about livestock grazing, agricultural water withdrawals and logging? And salmon are in trouble in coastal streams where there are no dams. The problem in part is that a lot of people don't agree there are multiple causes. There are still a lot of single-factor folks."

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