The city still plans to use Rotenone on Riel Pond despite not finding any stickleback in it during a recent survey.
St. Albert plans to apply the pesticide Rotenone to the stormwater pond by the Big Lake Environment Support Society (BLESS) observation platform sometime in the next two weeks in order to kill off an invasive fish, the threespine stickleback. The application was scheduled for Tuesday but was called off due to high winds.
A biologist surveyed the pond using electrofishing and minnow traps Monday to confirm the presence of the fish, said Leah Jackson, the city’s environmental manager. Surprisingly, he found just 17 fish — compared to about a hundred in previous surveys — none of which were stickleback. “No stickleback, no brook [stickleback], no threespine.”
Previous studies showed the pond contained threespine stickleback, native brook stickleback and fathead minnows. The small catch was likely the result of low water levels over winter, Jackson said.
This could suggest that the sticklebacks are gone, Jackson said, but provincial and federal officials aren’t convinced this is the case. “We couldn’t guarantee that was conclusive evidence of the eradication of the threespine,” she said, as the test could have missed some of the fish. “We’re going forward with the application.”
Low water levels plus the small number of fish should make the Rotenone more effective on any threespine in the pond, Jackson said.
St. Albert could see eight new grit interceptors in the next decade, built to keep dirt out of the Sturgeon River.
About 150 tandem dump trucks worth of grit have piled up in the Sturgeon River over the last 20 years, according to the city’s 2004 stormwater management plan, creating sandbars that disrupt river traffic and aesthetics. In 2004, the city made plans to build 26 hydrocarbon grit interceptors for $10 million over 10 years to keep grit out of the river. Two were built — one under St. Anne Street and one by the Boudreau Bridge — before the plan was axed in 2007.
The city wanted to figure out which interceptor worked best, said Jackson, reporting to council Monday: the concrete settling basin on St. Anne Street or the settling ponds by the bridge.
The St. Anne interceptor grabs seven truckloads of grit a year, her report found, but can’t keep chemicals out of the river. The Boudreau Bridge interceptor should stop grit and chemicals, but hasn’t worked properly during the last three years due to huge storms.
Jackson recommended that the city use settling ponds like the one at Boudreau Bridge where possible, provided they add a concrete settling basin to them to reduce maintenance costs.
Council accepted the report, and is expected to discuss implementation at its next 10-year capital plan review this summer.
Bird numbers were down at Big Lake this month due to a warm, early spring, says a local birder.
About 46 people gathered at the BLESS platform on the last two weekends for the annual Springing to Life event. The event, organized by birders Dan Stoker and Alan Hingston, celebrates the return of birds to Big Lake during spring.
The total bird count was down significantly compared to the last three years, said Stoker: just 1,800 were spotted, compared to 3,000 to 8,000 in previous years. “I think a lot of the birds have already gone through” on account of the warm weather, he said. This would also explain the low numbers of American wigeons and Canada geese, he added, as they tend to migrate early.
But watchers did get to spot birds that usually miss this event, Stoker said, such as the swamp sparrow. A drab brown bird, the swamp sparrow is usually seen and not heard, as was the case at this event. “It sounds like a little jackhammer going in the marsh,” he said, and is very tough to identify otherwise.
