A study is finding direct evidence that climate change is having on fish in Ontario’s lakes. The study tracked the movement of lake trout in hundreds of lakes in northwestern Ontario. Study lead Dr. Tim Bartley with the University of Guelph says an early study found lake trout retreating to deeper waters as lakes heat up.
“Many cold-adapted species, species that prefer cold water showed the same sort of response to climate change. So you can think about lakes as having two primary habitats. There’s a sort of near-shore surface water habitat and then a deep offshore cold habitat. Previous results that indicated that lake trout were responding to warming lakes by retreating into that cold offshore habitat. Our new results show that it’s not just lake trout. A dozen or so cold water species are all doing this moving into deeper colder water as the surface and near-shore waters are warmer with climate change,” says Bartley
Those species include whitefish, burbot, different types of minnows, ciscos and sticklebacks. Bartley says the finding could be cause for concerns to anglers and those in the baitfish industry.
“There are some possible real consequences to this. What we know from the data so far is that these species are moving into deeper water. What we’re not really sure yet is whether those species are experiencing consequences like reduced population numbers or changes in growth or have they been altering their feeding. So there’s a whole lot of possible outcomes to this change that might be concerning for anglers or other people that have a stake in what these cold water fish are doing,” says Bartley.
Bartley says the findings also point to climate change having a direct impact on area lakes.
“In this case, the evidence that climate change is real is really good. What we’re trying to do with this work is show that it has some really important consequences for how animals behave. The exciting part is that we think we can use those behavioral responses of these different species, be it moving down into the deeper water, we can use those behavioral responses to try to figure out what the consequences of climate change might be.”
