The latest kokanee spawning numbers in Kootenay Lake indicate a growing concern for anglers and conservationists.
According to the December 2021 Kootenay Lake Kokanee Recovery Update, 24,000 main-lake spawners were counted this fall.
The number reveals a significant decline compared to the 90,000 that returned in 2020, and well below an average of main-lake spawners that numbered between 250,000 and 1.5 million a decade ago.
The update, released by the Ministry of Forests, Lands and Natural Resource Operations and Rural Development, reveals the lowest number since the kokanee population crashed, going from 150,000 in 2014 to 18,000 in 2015, and an all-time low of 12,000 in 2017.
As a result, the Ministry said it is considering reducing the Gerrard rainbow spawning and juvenile trout populations in the Lardeau River to further reduce kokanee predation pressure and restore predator-prey balance.
“An expert advisory team reviewed the risks and benefits of such actions and suggested that benefits to kokanee recovery are likely, while risks are manageable if spawner reductions or reductions of juvenile fish are short-term (i.e., 1-2 years initially) and undertaken according to best management practices.”
The report, however, did offer some hope. Despite the decline in the kokanee population, in-lake surveys conducted in the fall indicate there is a healthy population of kokanee fry, about 17 million.
“In addition, juvenile (age 1-2) kokanee survival improved significantly in 2021, which is likely attributed to continued reductions of rainbow trout and bull trout in Kootenay Lake.”
The Ministry has taken measures to help improve the population, including kokanee stocking and reducing the predator population through modified angler regulations and the Kootenay Lake Angler Incentive program.
Recent efforts, however, show that neither stocking or increased catch limits have produced the desired effect.
In 2017, more than 8 million eggs were stocked in the Meadow Creek Spawning Channel and, of those only 15,000 adult spawners returned to the channel to spawn in 2021.
The ministry also oversaw the stocking of 1.1 million eggs in 2021, but considers predation the main factor in kokanee decline.
The ministry increased the angler retention limits of Gerrard rainbow to five per day and bull trout to three per day in an effort to reduce the population. In addition, the Kootenay Lake Angler Incentive program, which began in June 2020, has started its second year of rewarding anglers for their catch.
The program is a collaborative effort led by the B.C. Wildlife Federation and the West Arm Outdoors Club. Every rainbow or bull trout head submitted to various collection depots on the lake are entered into a monthly prize draw for $1,000 in gift certificates. Each entry also has a chance at three Grand Prize draws throughout the year.
The 2020-21 program saw approximately 11,000 heads entered, which contributed to the improved in-lake survival for age 1-2 kokanee in the last year.
Despite the actions, rainbow trout and bull trout spawning populations have remained above levels of conservation concern.
The Gerrard rainbow spawning numbers in the Lardeau River saw a sustained increase from 2009-14, and peaked in 2012 at 1,600, precipitating the decline in kokanee.
Spawning numbers have since declined to between 150-450 in recent years, with 250 counted in 2020. Gerrard and bull trout are resilient to over-fishing, and it takes a relatively low number of trout to produce a high supply of eggs for future generations.
“It takes very few (Gerrard) spawners to saturate the available juvenile habitat in streams,” said the report. “This means that there is additional room to reduce kokanee predation without risking conservation of these populations.”
Bull trout spawning populations suggest a declining population from 2017-2020. Catch rates for large bull trout are lower because of the reduced kokanee population, however, catch rates of smaller bull trout, less than 2 kg, are very high.
Decisions will be made on these specific actions based on recommendations from the team of experts, and in discussion with First Nations.