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A window into climate change on a warming Lake Huron

There’s nothing quite like dipping your toes in Lake Huron for the first time each spring. If you were down at the Port Elgin Main Beach in early April, you’d have seen children doing much more than that—splashing around, dunking under, shrieking as they surface in the chilly water.


Surprising for that time of year—but above-seasonal temperatures and lots of sunshine meant many families were itching to explore the shore.


But there’s another side to that warmer weather.


While Great Lakes water temperatures naturally fluctuate from year to year, last summer saw Lake Huron’s water five degrees warmer than average, according to the National Oceanic and Atmospheric Association’s (NOAA) Great Lakes Environmental Research Laboratory (original data here).


Those warming waters concern scientists like Dr. Joanna Wilson, Professor in McMaster University’s Department of Biology.


From local research to the future of Lake Huron

In her research through Environment@NII, Joanna and her team have found links between warmer water temperatures and threats to some of Lake Huron’s most popular—and commercial—species of fish.

Climate change may have a significant impact on Lake Huron’s fish and wildlife species, commercial operations, recreational activities—and so much more.

On Lake Huron, Bruce Power has been working to model what will happen to water temperatures under different climate change scenarios. The lake’s water temperatures are expected to increase, with similar results comparing scenarios with and without Bruce Power operations.


Since 2015, Bruce Power has been partnering with researchers at McMaster, the University of Regina and the Northern Ontario School of Medicine to examine how warmer water might affect cold-water fish species. Results from laboratory studies are used to understand how fish might respond to gradual increases in lake temperatures over time with researchers looking at survival, growth and development.


We sat down with Joanna to learn more about this research made possible by Bruce Power.

Water temperatures nearby Bruce Power don’t cause warming throughout the Great Lake—but this research is crucial to understanding the potential effects of climate change.


What are you trying to find out?

We began looking at the effects the Bruce Power site might have on nearby species of fish, particularly lake whitefish, round whitefish and yellow perch.


Our work aims to determine if increased water temperature affects fish embryo development and whether incubation temperatures can impact fish after they have hatched.

This research gives us a window into what could happen in the lake as it warms due to climate change.

Should we be worried about climate change effects in our lakes?

Researchers are predicting a two- to four-degree warming for the Great Lakes, on top of the major stressors already affecting the lakes: population increases in nearby communities, agricultural runoff, commercial fishing and shipping, and recreational activities.

If carbon emissions aren’t curbed, climate change is coming to our lakes—and we need to think about what’s going to happen to these ecosystems.

What we’re seeing is that warmer temperatures can be devastating to fish populations that are dependent on colder environments, like whitefish and yellow perch. If climate change predictions happen in the coming decades, we might not see native species like these in our lakes.


Can you walk us through your project?

First, we work with commercial and Indigenous fishing partners to determine when lake and round whitefish are ready to spawn.


We then bring embryos back to our lab at McMaster and incubate them in water of different temperatures:

  • normal Lake Huron conditions up to 2 °C

  • at 5 °C

  • and at 8 °C

What kind of effects are you seeing?

Temperature is a critical environmental condition for embryo development—and we have found that lake and round whitefish embryos experience increased mortality with higher temperatures.


Fish develop faster and hatch earlier at warmer temperatures—and when they hatch are noticeably smaller in size and develop differently.

Lake whitefish embryos. Panel A shows the head with large black eyes and a developing lower jaw. The large round structure in the lower right is the yolk sac, with an oil globule—this is what sustains the fish while it develops. Panel B shows the developing gill arches that will be critical for oxygen uptake in the hatched fish. And Panel C shows the whole fish from a top view, with the developing pectoral fins.


How are they developing differently?

With higher water temperatures during their development as embryos, the fish have smaller mouths, which may limit what they can eat once their yolk sac is depleted.


As well, their fins are smaller so that may hamper their ability to move around while seeking out food.


And you’ve found that the warmer water affects them after they hatch, too?

Yes—the higher water temperatures continue to negatively impact the fish, as it causes their basal metabolism to be higher, so they need more food.


Just like an Olympic athlete needs to take in more calories because their basal metabolism is much higher than a sedentary person’s, these fish need more food after they hatch.


The difference is the fish may not have the ability to capture and consume enough because of the development changes I just mentioned.


Why does this work excite you?

I’ve always enjoyed being around water, and I think fish are so interesting. Being out in the field is enjoyable—going out in a boat or walking the shoreline in hip waders—some trips we’ll even camp out over several days.

Being out in the field anchors you in the research, connecting you with the organisms you study in an important way.

Embryos are considered a very sensitive life stage and temperature is a critical environmental condition for development. I am always excited to work on native fish species, like in this project—and doing research on Lake Huron is a great way to spend your day.


What is the most important thing we don’t talk about when we talk about fish species in our lakes?

People are most interested in fish that they consume and/or are a target for sports fishing. There are many fish species that get overlooked if we only focus on those species that people most interact with.


We need to look broadly at different species because they all have an important ecological role.


We chose round whitefish, for example, because although they aren’t commercially fished like lake whitefish, they are an ecologically important species in Lake Huron—and, as it turns out, more temperature sensitive.


What do people need to know about climate change and our lakes?

Climate change and other large environmental issues often seem too big for any one person to do anything about. Yet it is the action of individuals, added up over the population and over time, that greatly contribute to environmental degradation.


People who live near the Great Lakes need to be aware that the choices they make in their everyday lives will matter. When there are so many people living and playing along the shoreline, small changes add up.


Note from NII: The Lake Huron Centre for Coastal Conservation has some excellent resources on its website about steps people living nearby the lake can take to help keep it healthy.