Fish traps set in Metolius River

Another important step has been taken on the Metolius River toward the reintroduction of salmon populations to Central Oregon.

Officials from the U.S. Geological Survey and Portland General Electric installed two large salmon smolt traps at the Gorge Campground, two miles downstream from Camp Sherman last week.

The traps are designed to capture live smolts for study.

One of the traps belongs to PGE and the other, which just arrived from a similar steelhead project in Idaho, was provided by USGS.

A PGE crew and boom-lift truck were on hand to facilitate assembly and installation of the traps in the river.

According to Mike Riehle, fisheries biologist for the U.S. Forest Service, 45,000 Chinook salmon fry were released near the headwaters of the Metolius River in January of this year.

Some 95,000 more fry will be introduced next month, and the traps will simultaneously start the process of gathering them back in for study.

The conical, five-foot diameter metal traps will serve to recapture the young salmon to study their survival rate, health, resistance to disease, and downstream progress.

As the fish grow and undergo "smoltification," they begin to migrate downstream in search of the sea.

Once in operation next month, the traps will be emptied daily through April, 2002.

One of the reasons for daily monitoring of the traps has to do with the river's healthy and voracious bull trout population. Big bull trout not only learn that the traps contain easy pickings, but they apparently are able to get in and out of the trap.

The current at the vortex of the trap is too strong for the small fish, but the big ones can get away -- after dining on the caged smolts.

Each trap is mounted on a 16-foot-long aluminum pontoon boat. The boats are collapsible and were assembled on site.

The completed assembly has a live holding pen at the end of a huge rotating funnel that channels the fish into the trap. The downstream end of the holding pen has a rotating drum that skims loose debris out of the trap.

PGE, the Forest Service, and the Warm Springs Tribes share a goal of returning anadromous (sea run) fish to the Deschutes basin. The current study will help evaluate the stream habitat potential for salmon survival.

Deanne Drake, a fisheries biologist for the USGS, was on hand to help set up the traps.

"It's a complex project," she said. "Our goal is to figure out how all the hatchery operations have affected wild stock. It's great to cooperate with PGE and the Tribes. A lot of people will benefit from this study."

Drake had high praise for the role played by the Warm Springs Tribes in the fisheries research project.

"All the fry are from the Warm Springs Hatchery," she said, "and the wild broodstock is from the wild run in the Warm Springs River."

She explained that the Tribes permitted use of wild fish for this purpose because of an unusually large return this year.

The last time a bumper crop returned was in 1996.

The Tribes routinely blend wild fish with their hatchery stocks to enhance genetic variety. One-third of the Metolius fry are from wild parents; another third originate from hatchery stock; and the final third have one wild parent and one hatchery parent.

The study hopes to evaluate the survivability of each of the three groups.

In order to distinguish among the three populations, the embryonic fish were exposed to subtle temperature changes during egg development.

The thermal variations produce permanent markings on an inner ear bone that will identify the fish later in life.

Drake said that PGE will also be radio-tagging some of the river's outbound Chinook to track them and evaluate how they do once they get to Lake Billy Chinook.

Riehle explained that once the young salmon get into the reservoir, they have a difficult time finding their way out because the outfall from the lake -- and, hence, the current flow -- is 250 feet below the surface.

"So," he said, "there's no obvious outlet for them to be attracted to. As a result, a smolt trap near the dam has not been particularly successful.

"One of the proposals," Riehle said, "is to move the outlet closer to the surface to attract the fish."

If the study confirms the survivability of the young salmon in the upper river, the next steps will be to evaluate, develop and install means for the permanent passage of anadromous fish around the dams.

In a related, but separate study, the viability of sockeye salmon in the Metolius system is also being examined.

Some 2,000 sockeye fry were included in the January release of Chinook fry, and 7,000 sockeye eggs were introduced into the river last month.

The eggs were placed in artificial redds. A redd is the equivalent of a salmon "nest" in the gravel.

Sockeye salmon require a rearing lake in the river system, and -- in Oregon -- sockeye are indigenous only to Wallowa and Suttle Lakes. Although the dams have closed down the sockeye runs to the sea, the species survives locally in the form of freshwater kokanee.

Kokanee and rainbow trout are the only anadromous fish that commonly adapt to a freshwater-only life cycle. Sea run rainbows are known as steelhead.

Together with Chinook salmon, sockeye and steelhead are the three species of anadromous fish native to Central Oregon.

Chinook and steelhead are also native to Squaw Creek, which flows through Sisters. Efforts are underway to restore those runs, as well. PGE has taken an increasingly active role in promoting salmon restoration throughout the region.

The effort is part of the process involved in the dam relicensing that comes due on December 31, 2001.