We examine how northern fishes are responding to environmental change. We use field-collected datasets that aim to incorporate the messiness of real-world ecosystems including numerous and potentially interacting environmental effects on biodiversity.

Current research interests include:

Tracking environmental change in northern aquatic systems
Examining the combined and interactive effects of climate and landscape changes on fish
Understanding how permafrost thaw may alter aquatic communities
Science to support evidence-based decision making

Tracking environmental change

Monitoring how northern aquatic ecosystems are changing is a critical first step in supporting the long-term conservation and adaptation of northern fishes. At higher latitudes, cold water species are facing a suite of environmental changes including rapid warming, changes in precipitation, declining ice cover, and novel pressures from warmer water species moving in.

Using a 30-year dataset, we examined how declining and culturally significant Yukon River Chinook salmon were influenced by numerous environmental and ecosystem processes acting over multiple life stages. Based on our results, we recommended key actions for conservation and management including protecting and restoring juvenile freshwater habitats, and developing a coordinated transboundary salmon recovery and rebuilding plan.

Key Resources

CBC news coverage: Environmental factors likely hurting Yukon River chinook salmon population, study says

Plain language report for decision makers created in collaboration with the Council of Yukon First Nations and sprucetip design

Murdoch, A., B.M. Connors, N.W.R. Lapointe, J. Mills-Flemming, S.J. Cooke, and C. Mantyka-Pringle. 2023. Multiple environmental drivers across life-stages influence Yukon River Chinook salmon productivity. Canadian Journal of Fisheries and Aquatic Sciences. https://doi.org/10.1139/cjfas-2022-0254

Feddern, M.L., E.R. Schoen, R. Shaftel, C.J. Cunningham, C. Chythlook, B.M. Connors, A.D. Murdoch, V.R. von Biela, and B. Woods. 2023. Kings of the north: Bridging disciplines to understand the effects of changing climate on Chinook salmon in the Arctic-Yukon-Kuskokwim Region. Fisheries. https://doi.org/10.1002/fsh.10923

Attending the Annual Yukon Salmon Ceremony and Gathering hosted by Little Salmon Carmacks First Nation, August 2022

Interactive effects of climate and landscape changes on fish biodiversity

Freshwater ecosystems are increasingly affected by various co-occurring threats or “cumulative effects” of human actions including urbanization, agriculture, resource development, and climate change. To further complicate things, both climate and landscape changes can often produce similar effects that may reinforce and amplify one other. For example, loss of stream cover due to logging or road building can accelerate the warming of lakes and rivers, with potentially negative consequences for fish that need cold, well-oxygenated water to thrive.

Understanding how cumulative climate and landscape changes may combine and potentially interact to influence biodiversity can help guide and strengthen climate adaptation strategies and land use planning efforts.

Key Resources

The use of natural outdoor laboratories can reduce threats to freshwater biodiversity

Canada’s invisible biodiversity crisis

Murdoch, A., D. Yip, S. J. Cooke, and C. Mantyka-Pringle. 2022. Evidence for the combined impacts of climate and landscape change on freshwater biodiversity in real-world environments: state of knowledge, research gaps, and field study design recommendations. Current Landscape Ecology Reports 7(4):68–82. https://doi.org/10.1007/s40823-022-00074-7

Murdoch, A., C. Mantyka-Pringle, and S. Sharma. 2020. The interactive effects of climate change and land use on boreal stream fish communities. Science of the Total Environment 700:134518. https://doi.org/10.1016/j.scitotenv.2019.134518

Historic mining tailings along the Klondike River, Yukon

Fish sampling in a rapidly changing permafrost region - Mackenzie Delta, Northwest Territories. Credit: Clay Steell

Understanding how permafrost thaw may alter aquatic communities

Climate warming and increasing human development are contributing to widespread permafrost degradation in northern regions, with potentially significant consequences for northern biodiversity and people. Thawing earth may lead to an increase in sediment and nutrient delivery to lakes. In turn, these changes can influence how clear the water is, as well as the aquatic plant habitat and food available for fish.

Key Resources

Plain language report for decision makers

Videos:

Multiple Stressors vs. Cold-Adapted Fish

Threats for Mackenzie Delta Fish

How will fish communities in Gwich’in and Inuvialuit lakes respond to climate change?

Murdoch, A., D. K. Gray, J. Korosi, J. M. Vucic, R. S. Cohen, and S. Sharma. 2021. Drivers of fish biodiversity in a rapidly changing permafrost landscape. Freshwater Biology 66(12):2301 - 2321. https://doi.org/10.1111/fwb.13834

Vucic, J. M., D. K. Gray, R. S. Cohen, M. Syed, A. D. Murdoch, and S. Sharma. 2020. Changes in water quality related to permafrost thaw may significantly impact zooplankton in small Arctic lakes. Ecological Applications:eap.2186. https://doi.org/10.1002/eap.2186

Past projects:

Amplified climate warming effects on Arctic fish

Arctic ecosystems are experiencing warming rates 2 to 3x global levels, with potentially devastating consequences for the cold-adapted species that reside there. These projects examined how warming may be impacting Arctic charr, one of the most cold-loving freshwater fishes on the planet.

We tracked fish migrations and used cutting-edge otolith (fish ‘earstones’) microchemistry techniques to assess how growth patterns were changing in response to warming. We learned that warming might be benefitting sea-run charr if they had access to colder and more productive marine habitats, whereas landlocked populations appeared to be more vulnerable.

These projects were in collaboration with the Nunavik Research Centre and Nayumivik Landholding Corporation in Kuujjuaq, Nunavik.

Murdoch, A., J. B. Dempson, F. Martin, and M. Power. 2015. Temperature-growth patterns of individually tagged anadromous Arctic charr Salvelinus alpinus in Ungava and Labrador, Canada. Ecology of Freshwater Fish 24(2):193–203. https://doi.org/10.1111/eff.12133

Murdoch, A., and M. Power. 2013. The effect of lake morphometry on thermal habitat use and growth in Arctic charr populations: implications for understanding climate-change impacts. Ecology of Freshwater Fish 22(3):453–466. https://doi.org/10.1111/eff.12039

Arctic charr otolith extracted for growth and temperature analyses in Murdoch & Power 2013

Subsistence fishery introduction

The community of Kuujjuaq, Nunavik implemented a novel community-based fishery introduction plan to a nearby lake system that aimed to supplement the local subsistence harvest. We wanted to know if adding this new species would disrupt the pre-existing foodweb.

Our research findings demonstrated that the freshwater foodweb was resilient to the introduction of anadromous Arctic charr in this system, thus providing valuable insight into the feasibility of creating similar programs for other northern remote communities with food security issues. As northern fish species are predicted to face increasing development pressures, sustainable fishery creation may be looked upon as an increasingly valuable means for offsetting current and future effects.

Murdoch, A., G. Klein, D. W. Doidge, and M. Power. 2013. Assessing the food web impacts of an anadromous Arctic charr introduction to a sub-Arctic watershed using stable isotopes. Fisheries Management and Ecology 20(4):302–314. https://doi.org/10.1111/fme.12012