Tracking the mysterious salmon with high-tech tools

TANANA (AP) -- It is like any other wall tent, one of dozens that can be found in fish camps all along this stretch of the Yukon River. Even a close inspection won't reveal much about what's on the other side of those canvas walls.

A step through the tent's double flaps is a step through time, a jarring juxtaposition of age-old tradition and ultra-modern technology, complete with modem, hard drive and satellite phone.

''It's incredible,'' Stan Zuray said with gee-whiz awe in his voice, ''especially when you consider two years ago I didn't know what 'Cap Lock' was.''

Surprisingly, we don't know much about salmon on the Yukon. Zuray's is one of three projects among several that are helping to clear up the rather murky life history of these fish.

With power by portable diesel generator and funds by the U.S. Fish and Wildlife Service, Zuray and his family are conducting cutting-edge research on this spot about 50 miles upriver from Tanana.

The Zurays are counting fish, which seems the most basic of tasks. The method, however, is not. Every evening Zuray hops into his boat and travels across the river to the family fish wheel, rests its spinning for the night and removes the micro-drive from a video camera mounted on the wooden frame.

A few minutes later, the Zurays can sit in front of a personal computer and watch an entire day's worth of salmon slide through a chute on the wheel, exit through a trap door and return to the river.

No more live boxes, which can harm the salmon, or standing around watching fish flop all day long. The video camera preserves 11 frames per fish, enough for Zuray to identify the species. He downloads the information onto a recordable compact disk and becomes a vital source of information for managers and scientists who depend on studies like this to make decisions.

''Our management can only be as good as the information we're provided to manage with,'' said fisheries biologist Russ Holder of the U.S. Fish and Wildlife Service.

The basics are in the books: Each year, king, chum and silver salmon return to the tributaries of their birth to spawn. Some travel most of the Yukon's 1,875 miles to complete a journey that began four to six years before when the previous generation completed the same feat, reproduced and died.

While predictable, the salmon remain elusive as they make their way against the current. The Yukon's chocolate-colored waters, changing face and depths of up to 70 feet hide many things from biologists -- important information like census numbers, migration routes and run composition.

The fish enter the mouth of the river in large pulses, mingling without regard to eventual destination. Scientists believe early fish are bound for the upper reaches into Canada and the later stocks take shorter trips. Yet, that simple assumption has already been put into doubt by a project that uses radio telemetry to track fish.

Logically, the first fish John Eiler and his crew tagged this summer should have made its way to Canada.

''It's interesting,'' Eiler said, ''Fish No.1 went up the Tanana.''

Like the Zurays' project, Eiler is using technology and techniques that weren't even thinkable five or 10 years ago. The National Marine Fisheries Service scientist is using radio tags and satellites to learn more about salmon runs. He knows that as the project continues, more assumptions will fall.

Next summer, Eiler hopes to tag more than 1,000 fish and track their progress. This year, Eiler's team captured and released a little more than 100 salmon and has had good success finding them by using tracking stations located in key spots along the Yukon, Anvik, Koyukuk and Tanana rivers.

Nearly 40 stations will be in place in 2002, watching the fish as they go. Every salmon tag emits a unique signal that is picked up by each station as it moves upstream. The day's information is uploaded to a satellite, which beams it back to Earth and a receiving station in Washington, D.C. Using a computer program designed specifically for the project, Eiler can watch the progress of each fish as it makes its way upstream.

The project, which also involves the Alaska Department of Fish and Game, will end up costing a couple million dollars. The tags alone are $180 apiece. And remote stations require the use of helicopters for implementation and maintenance. But the resulting information will be invaluable, researchers say, and will spread across several disciplines.

There are few things the people along the river agree on. The need for more research, however, is one of them.

''They've been using fairly primitive methods to try and census these fish,'' said longtime subsistence fisherman and Tanana resident Charlie Campbell. ''The more (research money), the better, as far as I'm concerned. It would be money well-spent. It's one of the last great wild salmon runs left in the world. It'd just be criminal to run this thing down into the ground.''

Another project watched with great interest is a study on a parasite named ichthyophonus, commonly referred to as ''Ick along the river.''

This parasite seems to infect 25 to 30 percent of the salmon population in the Yukon and has researchers worried it is affecting an already weakened stock. Ick attacks a salmon's vital organs, leaving flesh that is inedible for humans and that doesn't dry properly. Fishermen have seen the parasite for some time, but only recently did it manifest itself so strongly that it began to figure into the equation managers use to regulate the run.

This summer's work gave a hint about the parasite's favorite conditions, said Bill Fliris, a Tanana resident known as ''Fungus Man'' because of his work with a University of Washington researcher studying Ick's impact.

The river was characterized by unusually low temperatures due to a late breakup. At the same time, the number of fish showing lesions and looking outwardly stressed fell off the scale, although the parasite can still be found internally.

Yet, there is still more mystery than fact surround Ick. Even the most basic information remains elusive, as Fish and Game Yukon River manager Tom Vania pointed out: ''We haven't even confirmed that the parasite is causing mortality in the fish before they spawn.''