In the spring, fingerling salmon make their way downstream to the ocean, while some adults head upstream to spawn.  In the fall, other adult salmon return to their spawning grounds. At this time of the year, the Columbia River and its tributaries in the western United States are usually teeming with salmon.  But this year biologists and anglers report the second lowest run on record.  VOA's Paul Miller has more.

The agency that regulates the Columbia River -- the biggest American river that flows to the Pacific -- has closed it to commercial and sport fishing for salmon. The reason is the salmon simply aren't there. Scientists predicted a spring run of 200,000 to 250,000 salmon.  But only about 2,000 have passed through the Bonneville Dam on the Columbia in the western state of Oregon where Steve Fick operates a fishing business.

"Normally at this time of the year we would have several thousands of fish over the dam at Bonneville.  We don't know why they're not wanting to go up the fish ladder," says Steve.

One theory is that sea lions in or near the dam have feasted too heavily.  But since no one really knows why the fish haven't arrived, fishing was closed in an effort to save what few fish there are. Efforts are being made to increase the number of salmon.

The Lower Columbia Fish Enhancement Group checks to see whether the fish are thriving. They have built some debris snags. Tony Meyer, who works with the group, says the snags are doing their job.

"The fish are drawn to that type of habitat.  It gives protection from predators.  There are multi-age fish living in that site," says Mr. Meyer.

It's the latest effort to help the salmon.  Governments have also torn down dams that were obstacles to migration, or installed fish ladders that enable the salmon to bypass the dams. Now the federal government has signed off on the first comprehensive plan to restore threatened and endangered salmon in the lower Columbia River.

Bob Lohn, the regional fisheries director of the National Oceanic and Atmospheric Administration calls the plan an important milestone.  He says, "The big gains for salmon are no longer in improving the dams, the big gains are in improving the habitat in streams like these."

But with development, pollutants and runoff from logging and agriculture, it's going to be a challenge is to save the salmon, its habitat and sport fishing -- which feed the economies of small towns along the Columbia River.