EEB SEMINAR: MARCH 8

This week we are pleased to welcome Matthew Guzzo from the University of Manitoba.

Why do fish get smaller with warming?
A case study using long-term monitoring data from the Experimental Lakes Area, Canada

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There exists ample evidence of the impacts of climate change on Earth ecosystems. The most well-known changes are advances in phenology (i.e. earlier spring flowering events) and shifts in species distributions towards higher latitudes and altitudes. More recently, researchers have proclaimed that declines in the adult body sizes of ectotherms, including fishes, represent a third universal response to warming. Despite this claim, only a handful of studies have provided evidence that wild fish populations are becoming smaller, while even fewer have identified the mechanisms behind these declines. In this talk, Matthew will use long-term monitoring data collected from a reference lake within the Experimental Lakes Area to show that a cold-water predatory fish, the lake trout, has underwent declines in adult body size over the past 30+ years. He will then discuss how observed changes in growth and size-structure of this fish population relate to changes in the thermal conditions of the lake experienced over this same period and describe how lake trout behaviorally respond to such changes in lake temperatures. Finally, he will discuss how the findings from this case study provide support (or lack thereof) for various hypotheses that have been proposed to explain why the size of adult fish is reduced with warming.

Matthew Guzzo is a PhD student (currently awaiting his thesis defence) in Biological Sciences at the University of Manitoba, with supervisor Dr. Paul Blanchfield. Matthew’s thesis examines the impacts of climate change on temperate lake trout populations.

The EEB Seminars run weekly, on Thursdays, in the EEB Lounge of the BioSciences Complex, Room 4338, from 12:30-1:30pm.

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