Steelhead getting transmitters to help solve deadly mystery
Seattle Times staff reporter
BUCKLEY, Pierce County — The surgery took just four minutes.
From a makeshift operating room floating on the Puyallup River, biologist Andrew Berger sliced open a young fish and tucked a vitamin-sized transmitter into the folds of its belly.
While a colleague pumped water into the gasping steelhead's mouth, Berger quickly stitched the wound closed so the 8-inch smolt could continue its journey out to sea.
For Berger and other biologists with the Puyallup Tribe, the delicate operation on this and dozens of other young fish may help answer some pressing questions: Where, exactly, do steelhead go when they leave the rivers that flow to Puget Sound? And could that help explain why so many are dying?
Steelhead populations around Puget Sound have plummeted so dramatically recently that the federal government has proposed listing them for protection under the Endangered Species Act.
Yet steelhead, which are similar to rainbow trout but spend much of their lives in the ocean and return to rivers to spawn, have such complex life cycles that unraveling the mystery of their decline is cumbersome. And wildlife managers suspect the problem may have as much to do with time they spend in Puget Sound or the Pacific Ocean as it does with the health of rivers.
"The ocean is like this black box," said Brodie Antipa, a hatchery manager for the state Department of Fish and Wildlife. "We just don't know what's going on out there. Is it global warming? Is it pollution? Predators?"
Array of receivers
For the first time, young Puget Sound steelhead will be tracked by an array of receivers placed at intervals along Puget Sound and up the British Columbia coast. The transmitters in the fish emit signals that the receivers will pick up, allowing biologists to track smolts from the rivers to the Pacific and hopefully determine whether they die along the way or make it out to sea.
"It used to be that you count your fish when they go out, wait a few years and count them when they got back, and that's all you knew," said Jim Myers with the federal government's Northwest Fisheries Science Center in Seattle.
But scientists in British Columbia already have used these receivers to track dozens of fish by computer, watching as up to 40 percent of them died within a few weeks of leaving Canadian rivers.
"If we could figure out if that's happening here, we'd be way ahead of the game," Myers said.
Even if fish make it to open ocean past the range of the receivers, that may help biologists rule out problems in Puget Sound.
"It won't tell us exactly what's killing them, only whether they are making it from point A to point B," Antipa said.
The need for more knowledge about steelhead has grown more important.
In some river systems, such as the Puyallup, steelhead declines have become perilous, with spawning steelhead dropping from thousands to hundreds in a half-dozen years. Steelhead spawning nests, called reds, in one Puyallup tributary numbered about 400 a few years ago. Last year biologists found 32.
This spring, the tribe and state began capturing wild adult steelhead from a fish trap on the White River, a tributary of the Puyallup, and hauling them to a hatchery to rear more young because "people have started to hit panic mode," said Russ Ladley, resource director for the Puyallup Tribe.
Unlike hatcheries designed to create more opportunities for anglers, "we're so far down in the tubes we're just trying to stave off extinction, basically," Antipa said.
Yet the decline in steelhead is happening even in rivers where runs of some salmon, such as wild coho, are returning at the highest levels scientists have seen since record-keeping began more than a half-century ago. And while steelhead runs on Olympic Coast rivers appear strong, pristine river systems in British Columbia are also seeing declines.
Unlike the case for many salmon species, it's hard to predict how long young steelhead will stay in fresh water before jetting out to the ocean, or how long they will remain in the ocean before returning home to spawn. The entire cycle may take as little as three years, or as many as seven — if it happens at all. Some steelhead can spawn rainbow trout, and vice versa, though scientists aren't sure what triggers the transition.
In the ocean, steelhead typically stay within 100 feet of the surface, while many salmon species live deeper. And steelhead have been known to travel great distances: Some fish that can be traced to Puget Sound have been found a few hundred miles off Japan.
Even when runs are healthy, there are typically far fewer steelhead than salmon in the rivers — as few as one for every 100 chinook. Yet while steelhead often struggle when competing with other salmon species, strong runs of both coexisted through most of the 20th century.
"There's just a lot we don't know yet," said Emmett O'Connell, a spokesman for the Northwest Indian Fisheries Commission.
Craig Welch: 206-464-2093 or firstname.lastname@example.org
Copyright © 2006 The Seattle Times Company