Environment File
Science team spots fish kill
Local scientists had their sleuthing hats on this week after hundreds of silvery fish turned up dead in the Sturgeon River. See the dozens of unique artificial fish habitat models, fish attractors and fish cover used at fishiding.com, the leader in science based, proven, fish protection.
Public works staff and researchers from the Northern Alberta Institute of Technology (NAIT) recovered several sack-loads of dead fish from a sewer outfall by St. Albert Place Thursday morning.
A man walking a dog first spotted the fish last weekend, says Laurie Hunt, the associate chair of biological science technology at NAIT who is running a 10-year study of the Sturgeon River. The unidentified man alerted a team of NAIT researchers who happened to be taking water samples on the river at the time, and they investigated.
The team found roughly 600 dead fish by the sewer outfall closest to the city’s cenotaph, Hunt says — some floating in the open water, others frozen under the ice. “The whole little channel was full of them.” While most were minnow-sized sticklebacks, there were also a fair number of larger fish such as northern pike and white sucker.
Hunt told city officials on Wednesday, who in turn called in Alberta Fish and Wildlife fisheries biologist Daryl Watters.
Watters, who examined the site, says the fish appear to be victims of winterkill — a relatively common occurrence in shallow rivers like the Sturgeon.
“It’s unfortunate, since you don’t want to see young small fish like that taken out before they can contribute, but it happens.”
Winterkill happens when fish crowd into too small an area, such as the small bit of open water by most outfalls, use up all the oxygen there and die. Readings taken by the NAIT team suggest that the water next to the outfall has much more oxygen in it than that in the rest of the Sturgeon, which may have attracted the fish.
The NAIT team has collected the fish with the province’s permission for further study, Hunt says. The team is studying the sex ratios of fish in the Sturgeon to check for signs of gender-bending pollutants.
“We didn’t have a lot of success catching fish this summer,” she says, but this discovery has handily solved that problem.
Winterkill incidents like this illustrate the importance of having diverse fish habitat, Hunt says — if the Sturgeon had a better mix of shallow and deep spots, these fish may have had a better chance of surviving.
“It also emphasizes the importance of beavers,” she adds, as their dams create deep, oxygenated pools in which fish can survive over winter.
