There has been a significant decline in the Kokanee population out at Kootenay Lake near Creston, but a team of provincial biologists has completed a review with recommendations to tackle the issue.
The team, which includes staff from the Kootenay Trout Hatchery, Ktunaxa Nation Council and the B.C. Wildlife Federation, developed a set of priorities ranging from high, medium and low.
High priorities included reducing the kokanee quota from 15 to 0 per day, while increasing the quota for Gerrard trout—a natural predator—from two to four fish per day.
Other high priorities include working with the Freshwater Fisheries Society of B.C. (FFSBC) to collect five million Kokanee eggs and to raise an additional 500,000 for release in the spring of 2016.
There are also a laundry list of medium and low priorities, which range from increasing Bull trout daily quotas and allowing more than two rods per person out on the water to actions such as stream habitat improvements.
“Basically, actions like regulation changes will increase the number of kokanee spawning (directly through no angler harvest, and indirectly through angler removal of kokanee predators) this year, and the next few years, and increase the number of kokanee eggs incubating to produce additional fry as a building block for recovery,” said Jeff Burrows, a biologist with the Fish and Wildlife branch of the Ministry of Forests, Lands, and Natural Resource Operations.
Kokanee spawning numbers plummeted in 2014 after a recent maximum had been recorded three years previously.
The review from the provincial team concluded that the most dominant contributing factor was the large number of Bull trout in Kootenay Lake that preyed on the Kokanee population, said Burrows.
“For example, the number of Gerrard rainbow trout spawning in each of the six years between 2009-14 was unprecedented in the historical record since 1960,” he continued. “…The kokanee population of Kootenay Lake supported these predators for a period of time, but eventually were unable to sustain the predation pressure and dropped rapidly in abundance from 2012 to 2014.”
Complicating numbers was the discovery of a virus—Infectious Hematopoietic Necrosis (IHN)—in 2013 that affects the survival rate of newly hatched or juvenile forms of rainbow trout and various salmon species. IHN is not harmful to adult fish and egg-to-fry survival rates have remained normal despite identification of the virus in adult spawners.
The ministry doesn’t anticipate IHN will affect kokanee survival rates in the long-term, but are continuing to monitor the fry leaving the Meadow Creek spawning area.
The Kootenay Trout Hatchery contributed to the review with staffing and expertise.
“With the Kootenay Trout hatchery, the Eastshore Freshwater Habitat Society and the help of local high school students, we have already released 95,000 kokanee fry to Crawford and Hendryx creeks in May,” noted Burrows.
“And this fall, the FFSBC will undertake to collect several million kokanee eggs from other locations in B.C. to outplant in suitable Kootenay Lake tributary locations, and as fry next spring.”