MOSCOW, Idaho – They’re green, eel-like and incredibly difficult to raise in captivity, but Kootenai River burbot are now successfully spawning in plastic tanks at the University of Idaho.
The tasty, freshwater codfish once sustained the Kootenai Tribe through the coldest months of winter, but fewer than 40 wild burbot are believed to be in the river today. In a desperate move to keep the fish from vanishing – and until the politically sticky questions can be addressed about why the fish are in trouble in the first place – the tribe is placing its hopes on setting up a hatchery.
Problem is, nobody in the world has been able to figure out a way to raise the fish. They spawn in winter under ice, and young burbot eat things like bugs, plankton and other creatures found in only wild rivers.
“Nobody has ever cultured this fish before,” said Sue Ireland, fisheries biologist for the Kootenai Tribe of Idaho. “This is really feeling in the dark.”
It’s getting a bit less dark, though. Four years ago, researchers at the University of Idaho began tackling the problem, courtesy of funding from the tribe, the Idaho Fish and Game Department and the Bonneville Power Administration. The project started with several adult burbot taken from Moyie Lake in southeastern British Columbia. The lake has a relatively healthy population of burbot and is genetically linked with the Kootenai River fish.
The fish were placed in plastic vats, which are about the size of a hot tub, except the 300-gallon reservoirs are anything but warm. Using special refrigeration devices, the water was chilled to just above freezing. With the water cold, nature soon took over. Groups of the fish writhed and swarmed in tight clusters known as spawning balls.
In short order, tiny, applesauce-colored eggs were released and fertilized. Not long after, the next generation of burbot hatched in a cold, stand-alone warehouse on the University of Idaho campus, some 200 miles south of river that has been their species’ home for thousands of years.
Getting the burbot to breed turned out to be the easy part, said Ken Cain, associate professor of aquaculture and fish health at the University of Idaho. The tough part has turned out to be feeding the young fish.
“Very little information is out there. Very few people have tried to raise the species,” Cain said on a recent afternoon, standing in the warehouse next to the burbot vats. The room was filled with the hum from refrigerators and the faint whooshing of air bubbles in the water tanks.
Larval ling cod don’t even have a mouth for the first 10 days of life. But once their yolk sack is depleted, the young fish begin slurping up plankton. Plankton can be grown in tanks, but the next course of food has proven to be more difficult.
Cain is now trying to find a way to wean the fish from plankton to a commercially available pellet fish food. The transition is proving to be the bottleneck in the process, but slow progress is being made.
“Each year we’ve gotten more fish up to size,” he said. “When we first started this we had no idea whether we could bring them into captivity and even get them to spawn.”
Cain flipped open the lid on one of the vats. Four-year-old burbot swam lazily on the bottom. These foot-long fish were the products of that first year of breeding.
“They seem to be very healthy,” Cain said.
Cain also helped the tribe develop a successful aquaculture program for the endangered Kootenai River white sturgeon. Since 1992, the tribe’s hatchery has released about 80,000 sturgeon into the river, said Ireland, the tribe’s fisheries biologist.
Followup sampling has shown high survival rates for the sturgeon, but the fish farms are not meant to be a longterm solution to keeping either sturgeon or burbot from extinction, Ireland said. The tribe is simply using aquaculture as a form of genetic duct tape to keep the species in the river until the cause of the problems are addressed – namely the operation of Libby Dam.
“They’re probably going to go extinct before we get anything done,” Ireland said. “But we need to do everything we can in the short term to help the fish. … We’re not using the hatchery as a substitute, it’s just all these things take time.”
Native fish species in the Kootenai River began to collapse shortly after 1972, when Libby Dam was built upstream in Montana. Now, the river is no longer covered with ice in winter. Not only is it too warm to induce spawning, but the burbot are not strong enough to swim upstream through high wintertime flows, said Vaughn Paragamian, fisheries research biologist for the Idaho Department of Fish and Game and the agency’s Kootenai River recovery team leader.
An intense effort is underway to find a more fish-friendly way of managing Libby Dam, but balancing this need along with flood control and power generation is proving to be tough and politically explosive. A lawsuit is now involved. The river’s operation and the fate of the burbot are in the hands of politicians and the courts.
Paragamian, whose devotion to burbot recovery has earned him the nicknames “Codfather” and “Lord of the Lings” from some of his biologist colleagues, said it’s frustrating to see the species disappear so quickly from a river that was once believed to have the strongest burbot fishery in North America.
“It’s like having your kid brother get beat up day after day and not being able to do anything,” he said.
Since 2005, the Kootenai Tribe and the state of Idaho have been adding nutrients to the river in hopes of boosting algae and other food sources for insects, which in turn feed fish. Efforts also are underway to improve spawning habitat, but the species has no longterm hope until wintertime flows can somehow be slowed and cooled, Paragamian said.
Until then, adding farm-grown fish will help keep burbot in the Kootenai River.
“It’s important we get fish out there soon,” Paragamian said, adding that sampling conducted over the past seven weeks in the river has failed to turn up a single burbot.
“I’m just going to remain optimistic. As long as I’m in this position I’m going to do everything I possibly can to ensure that someday fishermen in Idaho can fish for burbot again.”