The crows, loons and ospreys have had a feast up on the Aberdeen Plateau northeast of Kelowna the past week.
A valve on the outlet of 138-hectare Grizzly Lake jammed open and the water reservoir was drained, stranding thousands of trout in the remaining pool of water below the outlet and in the spillway below the dam.
When environment ministry fisheries biologist Brian Jantz heard about the drawdown, he immediately made a few calls to try and round up help to undertake a fish rescue operation on the weekend.
As a result, an estimated 40 volunteers from at least four fish and wildlife clubs met at the site and spent Sunday netting 10,000 trout from the spillway and transferring them by plastic bins to a large tank mounted on a Go Fish B.C. truck for transport to a nearby natural lake.
Jantz had estimated the number of fish in the spillway at about 200 prior to the rescue, although the ministry stocked the lake this year with 3,000 trout.
There’s obviously a healthy natural population of trout as well, he said, after the day’s work.
The fish ranged in size from fry to four-year-olds.
Among the volunteers who gathered to net fish, lug heavy buckets and drive the ATVs carrying fish to the tank, was Al Cotsworth, manager of water for Greater Vernon Services, which operates the reservoir.
Cotsworth says they didn’t realize how far open the valve had jammed, or how quickly the shallow lake would drain.
When they discovered how fast it was dropping on Tuesday last week, he says they contacted the water stewardship branch of the ministry, which notified Jantz.
He says the earthen dam was built in 1980, and 26 years is a long time for a submerged piece of equipment to operate without any problems.
A system has now been set in place to ensure fisheries will be notified sooner if there is such a problem again, says Cotsworth.
However, he notes that historically, there would have been a quite different ecology on that site, not one that would have been fish habitat.
Since the area was flooded the water level varies about 12 feet a year and the lake’s maximum depth is 31 feet, he said.
Jantz said there was also a massive fish kill at Grizzly in 1987, but because the outlet is so low on the lake, it’s unusual in how low it will drain.
Low water is an issue occasionally at other recreational lakes which double as domestic water reservoirs.
He was impressed by the great turnout, on short notice, of so many volunteers of all ages, who made their way up to the lake.
It is at an elevation of about 4,200 feet, between Kelowna and Vernon.
“It was fabulous. I was overwhelmed by the response. People really rallied. It was a great experience,” he commented.
“It was neat to have everyone pulling together like that. The volunteers all worked really hard and realized the urgency of the situation,” he added.
The ministry stocks dozens of reservoir lakes in the Okanagan, but many have begun as natural lakes, so there’s what’s called “dead storage” below which the lakes can’t be drawn down.
That protects them from such fish kills as would have occurred at Grizzly this week.
Rick Simpson, fisheries co-chair for the Okanagan Region of the B.C. Wildlife Federation, said members of the Peachland Sportsman’s Association, Oceola Fish and Game Club, Kalamalka Fly Fishers’ Club, Lumby and District Wildlife Association and Okanagan Nation Alliance came out to work on the project.
As well, staff from the ministry, the Freshwater Fisheries Society of B.C., Greater Vernon Services and B.C. Parks showed up to help.