The population of kokanee in Okanagan Lake has grown to about 17 million from less than 15 million two years ago, fisheries officials estimate.
The one million per year fry from Skaha hatchery being put into Okanagan Lake for the past two years have contributed greatly to this increase, fisheries biologist Bruce Shepherd said.
“We have more hatchery fish showing up in our catches than we would expect.”
Using their new research boat, fisheries technicians net fish in the lake to check them. They also count fish with echo sounding equipment.
Because kokanee run in schools at very specific water depths and at certain times, a very accurate estimate of numbers can be obtained through echo sounding, Shepherd said.
Initial experiments with hatchery kokanee in Skaha Lake several years ago were not successful. Few of the hatchery fish lived to be adults.
Shepherd said experiments with kokanee in similar small, relatively shallow lakes in the United States were also unsuccessful.
But Okanagan Lake is another story.
So far the supply of fresh underground water at the Skaha hatchery has kept the fry there relatively disease free and they appear to be doing well.
Fry being released weigh up to two grams. Fish from natural spawning beds weigh only about1/3 of a gram when they enter the lake so have far less of a chance of evading predators and surviving.