Researchers study effect of invasive fish species

Researchers are plumbing the depths of 150 mountain lakes in national parks across Alberta and British Columbia to better understand the lasting impact of the introduction of invasive sports fish in the last century.

Up until Canada’s mountain parks in Jasper, Banff, Waterton, Kootenay and Yoho were declared UNESCO World Heritage Sites in the 1980s, there was a concerted campaign to populate previously fish-barren lakes with three species of non-native trout to lure fishermen and tourists to the region.

The problem was the shortterm gratification of bringing in tourism revenue was never correctly balanced with the longterm effects of introducing rainbow, eastern brook and European brown trout to the water bodies.

Those species caused irreparable damage to some of this country’s most pristine lakes, says University of Alberta biological sciences professor Rolf Vinebrooke.

And some of those alpine lakes may not yet have recovered.

“There wasn’t a great deal of interest in the recovery of these ecosystems as opposed to determining whether or not they were good for fish stocks,” Vinebrooke says.

But there is now. Vinebrooke and six University of Alberta students are undertaking an expansive research project in the mountains to check on the health of the lakes and how they are responding to the effects of climate change.

“The higher temperatures and presence of exotic sports fish sort of synergistically amplify each other’s effects, thus having a greater impact on the lake ecosystem than if you just added up the sum of their two individual effects,” he says.

Thanks to similar surveys conducted at various points in the 1900s, they have baseline data with which to compare their fresh results.

The study involves measuring the chemical and physical environment of each lake through water chemistry analysis, light penetration and temperature profiles, along with collecting biological indicators like phytoplankton and zooplankton.

“Then all the fun the students are having in the field comes to a halt and then all the laboratory analysis starts,” says Vinebrooke.

While not specifically sampling fish stocks this year, there are plans to later sample water columns and determine through environmental DNA in the water if there are specific fish species remaining in the water.

They need not rush because a trained ecologist can look at the data they are collecting and, with a pretty fair degree of confidence, adds Vinebrooke, determine whether or not there is fish in that system.

The higher temperatures and presence of exotic sports fish sort of synergistically amplify each other’s effects ...