The annual harvest of burbot from the Kootenai River by sport and commercial fisherman in north Idaho’s panhandle “prior to 1972 was likely in the tens of thousands of kg,” according to a 2011-2016 research plan developed to further restoration of what has become a decimated species.
Overfishing, dam construction and operations, the diking of off-stream habitat and other factors are believed the causes for Kootenai burbot stock shrinking to functional extinction.
The Kootenai Tribe of Idaho, a culture that was long sustained by native species such as burbot, is leading a long running effort to restore degraded habitats and, as a result, enable native fish stocks such as white sturgeon and burbot to regain some of their historic strength and in the process allow fisheries that have been shut off since the 1970s.
Key in those restoration efforts is a budding, experimental burbot aquaculture program centered for now at the University of Idaho in Moscow where culturing techniques are being developed with broodstock from British Columbia’s Moyie Lake. The tribe has in the works plans for construction of a new hatchery near the Moyie River’s confluence with the Kootenai River that will allow expanded production of both white sturgeon and burbot.
The goal for the tribe’s burbot aquaculture program, now in an experimental phase, is to reestablish a native burbot population in the lower Kootenai River capable of future tribal treaty subsistence and cultural harvest and sport harvest once the population reaches sustainable levels.
The new hatchery will also allow the tribe to fully implement the native burbot conservation aquaculture program.
The idea at this point is to boost populations to the point that enough adult fish – burbot released into the river and its adjacent environs at the larval and older stages -- are present to incorporate them into the broodstock.
Among the goals of the Kootenai Tribe’s program, which is largely funded by the Bonneville Power Administration, is to implement a plan to reverse the population decline through habitat restoration, and research to identify and address gaps in the understanding of the specific causes of population decline. The conservation aquaculture program is being implemented to reverse population declines and rebuild a population with demographic and genetic characteristics to ultimately become sustainable and resilient.
The burbot (Lota lota) is a landlocked species of cod. The Kootenai River flows out of British Columbia into northwest Montana, into north Idaho, and then north again into Canada where it becomes the Kootenay. North of the border it enters the reservoir called Kootenay Lake. It ultimately exits and joins the Columbia River. The Moyie River also flows south out of British Columbia, joining the Kootenai in north Idaho just west of the Montana border.
Burbot historically were a prized, tasty catch. They were reported to have ranged in size from 18 to 42 inches, but were more commonly in the two to three foot range; some of the larger ones weighed ten or more pounds.
The burbot’s presence in the Idaho section of the Kootenai River had dwindled to the point that when aquaculture experimentation began in 2002, researchers did not want to mine the sparse native population for broodstock. And they didn’t know if they could even find any fish to mine.
“There’s barely any natural recruitment,” said Shawn Young, the Kootenai Tribe biologist that is heading up the aquaculture project. The Moyie Lake population, considered to be stable, was judged because of the relative proximity and other factors to be the best matched genetic “donor” stock that could be used to rekindle the Kootenai River population.
The project is being carried out in collaboration with the British Columbia Ministry of the Environment, Idaho Fish and Game, U.S. Fish and Wildlife Service and the University of Idaho’s Aquaculture Research Institute. Basic culture methods have now been established and documented for spawning, egg incubation, larval rearing and juvenile grow out.
The first experimental releases took place in October and November of 2009, numbering just a few hundred. That crop included about 200 fish that were slightly less than a year old and about 60 or 70 that were in the 1-2-year-old range… and a sprinkling of 3 year olds, said UI researcher Ken Cain.
That represented considerable progress in fewer than 10 years, given the problems faced in growing burbot for the first time at the laboratory. The UI facility is one of the few around the world where burbot culture is being explored.
The program began with Moyie broodstock captured in the fall of 2003; the first year of spawning in captivity occurred in 2004. Cain said that first year the lab produced only four fish from six million eggs.
The program has grown through experimentation and identification of rearing technices..
“Last year we put out a substantial release of 6-month old fish,” Young said. The 2011 releases included 50,000 larvae and 20,000 6-month-old fish.
“There’s a big difference,” Young said. The older the fish are at release, the more likely it is they will survive.
The program has released some 1, 2 and 3 year old burbot but in small numbers. Space at the UI laboratory is limited so there’s little space available to grow out the fish. That problem would be solved if the tribe’s hatchery proposal makes it through the final planning stages and construction funding is through the Northwest Power and Conservation Council’s fish and wildlife program, which is funded by Bonneville.
But hatching and rearing techniques have been honed to the point that larvae are being produced in relatively large numbers.
A stumbling block had been getting the newly hatched fish, encased in a nourishing yoke sac, to feeding on their own.
“Once we get them to a certain size they’re pretty hardy,” Cain said. The researchers gained that success by raising plankton of a suitable size – small – in the laboratory.
The newly hatched burbot are so small that “they don’t even have a mouth for the first 10 days,” Cain said.
“They have a short window to begin feeding,” Young said. “They need a fairly steady food source.
The culturing is ongoing.
“Now the M&E will begin to get ramped up,” in an attempt to evaluate if fish survived, and where they went, Young said. A strong sampling of fish has been outfitted with PIT tags so they could be detected later. This summer the first large scale sampling of smaller PIT-tagged burbot will be conducted by the IDFG.
Larger fish – the 1, 2 and 3 year olds released, were equipped with acoustic tags so their movements could be tracked.
“We’ve seen extensive dispersal” up into Kootenay Lake and throughout the Idaho portion of the Kootenai River, Young said. Some of the fish were detected in known spawning areas. But it is not known yet if spawning took place. The number of supplemented fish that are of spawning age fish remains small.
“They went to the proper areas at the proper time of the year so we assume they are spawning, a few of them,” Young said. Burbot begin reproducing on average at about age 4.
But hopes are high.
“It’s a good project,” said Young, who was out this morning helping to release a new batch of larvae delivered from the overflowing UI lab fish tanks. “And it seems to be going pretty well.”