Effort aims to restore once-abundant burbot in Kootenai River
Snow was blowing sideways when Corie Laude hauled a hoop net from the choppy waters of the Kootenai River. Her catch lurked in the bottom of the net, green and alien-looking.
The creature’s long, sinuous body gave it an eel-like appearance. Feelers rose from its nostrils like miniature antennae.
The fish was a rare find, a type of freshwater cod called burbot.
The Kootenai River once supported one of North America’s largest burbot fisheries. Each winter, Native Americans and commercial fishermen took thousands of burbot from the river, its tributaries and British Columbia’s Kootenay Lake. The runs were so abundant that the burbot choked spawning streams.
“People speared them in creeks with pitchforks,” said Laude, a fisheries technician for the Idaho Department of Fish and Game. The delicate-tasting flesh was known as “poor man’s lobster.”
Today, fewer than 50 adult burbot are believed to remain in the Kootenai River system. By most measures, they’re considered extinct. But the otherworldly-looking fish have devoted fans among fish biologists, who don’t want the Kootenai’s genetically distinct burbot stock to disappear.
For the past 20 years, burbot have been the subject of intense study among state, federal, university and tribal biologists.
“They’re such an interesting fish,” Laude said. “They’re not your average trout.”
Burbot are known for their predatory instincts. An 8-pound burbot can swallow a 3-pound prey fish.
“The burbot is an important fish in the suite of native species that live in the Kootenai River,” said Sue Ireland, fish and wildlife director for the Kootenai Tribe of Idaho. “They’re part of the food chain and culturally significant to the Kootenai Tribe.”
To augment the faltering population, the tribe began releasing young, hatchery-raised burbot into the Kootenai River two years ago. The adults are captured at Moyie Lake in British Columbia, whose healthy burbot population is genetically linked to the Kootenai’s. The eggs are hatched and reared at the University of Idaho’s aquaculture research center.
But the cross-border effort to save the burbot faces steep challenges, as evidenced by Laude’s catch rates. She’s set dozens of traps this winter at burbot spawning grounds near Bonners Ferry, Idaho, and at the mouth of the Goat River, a B.C. tributary of the Kootenai.
The traps have netted just three burbot. Some years, biologists catch only one or two fish.
Biologists attribute the burbot’s demise to a variety of factors. The stocks were depleted through overfishing. And the river’s habitat has changed drastically over the past century, most significantly by Libby Dam’s construction in 1972.
Changes to the river have hampered reproduction. Unlike other freshwater fish, female burbot release their eggs for males to fertilize in the dead of winter.
Winter spawning is an evolutionary trait for burbot, a 5-million-year-old offshoot of marine cod, said Vaughn Paragamian, a fisheries research biologist for Idaho Fish and Game. When burbot became landlocked, they retained characteristics from their oceangoing days, including an adaptation to chilly water.
During the winter, when other fish are sluggish and inactive, burbot prowl the Kootenai in search of partners.
But Libby Dam has altered conditions conducive to hookups. During the winter, the U.S. Army Corps of Engineers releases water through the dam to generate electricity. Corps officials also draft the dam’s reservoir for flood control.
As a result, flows in the Kootenai are three to four times higher than historic levels. Water temperatures, which once hovered near freezing, are eight to 10 degrees warmer.
“From a fisheries standpoint, lots of bad things have happened to the Kootenai River ecosystem,” Paragamian said. “It’s been dredged, it’s been diked, and it’s been cut off from its flood plain. But Libby Dam is really what turned the river inside out.”
Paragamian has observed burbot moving upriver to spawning sites, then turning back. They have difficulty navigating the higher velocities, he said. Egg incubation also suffers from the warmer temperatures.
Nicknamed “the cod father” by his colleagues, Paragamian has spent 18 years studying the Kootenai burbot. He theorizes that the higher flows and warmer water have probably pushed back the burbot’s spawning season by four to six weeks each year, from December to late January or early February.
By adjusting gates at Libby Dam, the corps has been able to release deeper, colder water from the reservoir, said Greg Hoffman, a corps biologist. But the temperatures are still warmer than historic conditions, he said.
Other aspects of the dam’s operation are harder to change, Hoffman added.
The Northwest’s demand for electricity peaks in the winter. That’s when the Bonneville Power Administration, Libby Dam’s owner, wants to maximize its hydropower output. The dam’s flood control operations, meanwhile, are governed by an international treaty.
Solving technical and political issues related to Libby Dam will take years, maybe decades. To keep burbot afloat until river conditions improve, fish biologists are pinning their hopes on the hatchery-raised fish.
Fourteen hundred young burbot have been released into the river over the past two years. To boost cultivation, the Kootenai Tribe plans to open its own hatchery, which would also rear white sturgeon.
The tribe has asked the Bonneville Power Administration for money to build the hatchery. It’s still in the design phase, but Ireland anticipates that construction will begin in late 2012 or early 2013.
Paragamian will retire from Idaho Fish and Game this spring. He’s doubtful that the Kootenai burbot will recover without significant changes to Libby Dam’s operation. But he’s hopeful about the research that’s been done over the past two decades. Biologists have a much better understanding of what Kootenai burbot need to survive.
“When I started this, people told me, ‘Don’t be surprised if you don’t find any burbot in the Kootenai,’ ” Paragamian said. “They thought they were all gone.”
As it turned out, a few tenacious fish remained.