Climate change affecting fish in Ontario lakes

Date:  March 22, 2019

Source:  University of Guelph

Warmer temperatures are having a ripple effect on food webs in Ontario lakes, according to a new University of Guelph study.

Researchers have found warmer average temperatures over the past decade have forced fish to forage in deeper water. There they hunt different prey species, causing a climate-induced "rewiring" of food webs, altering the flow of energy and nutrients in the lake.

Monitoring the movement of generalist species like lake trout may offer an early warning system for impacts of climate change on ecosystems.

"We can harness the natural capacity of species to detect and respond to changes in their environment," said Tim Bartley, a post-doc in the Department of Integrative Biology and study lead author. "As species are changing their behaviour, they are telling us about what's happening around them in their environment. We can use this information. The behavioural changes we see imply major reorganization of ecosystems."

Published in the journal Nature Ecology and Evolution, the study entailed tracking lake trout movement and feeding in hundreds of lakes in northwestern Ontario.

Bartley caught fish to analyze their tissues to see what they ate. The team also used similar data about fish feeding habits and locations across the province from the Ontario Ministry of Natural Resources.

Read more