Join us in-person on August 8 for a project update

Hey folks - this blog hasn't been as active as I'd like it to have been (so far), but our annual meeting is coming up again here soon which is a great chance to connect with me and the project team in person, get some glimpses at what we're finding with our fish tracking data on Stoney, and give input on the future of the project.

We're hosting a public meeting at Viamede on Saturday August 8 at 2PM. The invite that's been sent out is copied below; all are welcome but we're asking for RSVP's this year. Please forward to anyone you think may be interested. Hope to see you there!

If you have any questions in the meantime, including about this event, feel free to email me: grahamraby@trentu.ca

Graham

You are invited to the 5th annual gathering to hear updates about the Stoney Lake Fish Tracking Project. For this meeting, we are inviting residents and cottagers from Clear, Stoney and Upper Stoney who have an interest in the ongoing research activities, learning more about the health of our lakes and Trent University’s work in communities.

There will be presentations by myself, Dr. Graham Raby, about a fish tracking project we’ve been conducting on Stoney Lake since 2022. Dr. Jake Brownscombe (Scientist for Fisheries and Oceans Canada) and Emily Swick (MSc student) also spend time providing a glimpse at our findings about fish behaviour and their habitat preferences. After the presentation there will be a Q&A session and an opportunity to give feedback to shape the direction of the research.

Ben Samann and Viamede Resort have generously offered to provide their space for this event.

Event Details:🗓 Saturday, August 8, 2026🕑 2:00 p.m. – 3:30 p.m.📍 Kawartha Room, Viamede Resort 595 Mt Julian Viamede Rd, Woodview, ON K0L 3E0

Parking is available in Viamede’s three parking lots and docking will be available if you arrive by boat.

Please RSVP here.

Thank you and we hope you can attend.

Dr. Graham Raby Assistant Professor, Biology Trent University

Exploring the use of underwater video for fish monitoring in the Kawarthas: part 2

By Jacob Bowman

Jacob was an undergraduate student in the Raby Lab when he conducted this work, and is currently an M.Sc. student working out of the Harkness Laboratory of Fisheries Research

It has been 3 years since my first Stoney Lake blog post about using remote underwater video (RUV) to study fish populations in the Kawarthas. Since we have recently published a scientific paper resulting from this work, Graham and I thought an updated blog post would be fitting.

            Fish have tremendous ecological and cultural value in the Kawarthas, so monitoring their populations is important. Conventionally, we assess the status of fish populations using methods like gill netting, that involve catching lots of fish, leading to injuries and deaths. RUV could be used to monitor populations without the need to catch any fish. There are two main things that fish surveys aim to measure: species richness (how many species are present) and abundance (the number of individuals of each species). The objective of my project was to assess how the estimates of species richness and abundance from RUV compare to those from other methods. We sampled Upper Stoney Lake and the Otonabee River to compare RUV to three more conventional techniques for assessing fisheries: minnow trapping, snorkel transects, and seine netting (netting at Otonabee sites only). Minnow trapping and seine netting involving capturing fish, whereas snorkelling is a non-invasive method like RUV. At each site, we would deploy a RUV system (Figure 1) for 1-hour, recording continuously. We then sampled the same areas with the other methods to get estimates of species richness and abundance.

The camera field-of-view for this study; showing a common carp swimming into view.

We found that RUV estimated similar or higher species richness when compared with minnow traps and snorkeling, meaning that overall it was as good or better than these other methods. However, seine netting caught more species than RUV. Small-bodied species like minnows were detected poorly by RUV because they were difficult to identify in the camera field of view, relative to when they could be examined when captured. The seine net we used covered a large area (100 m²) and had a fine mesh, so fish in that area were unlikely to escape or be missed.

            Because fish can frequently swim through the camera field of view, it is difficult to count individuals (there are some sample videos below). The simplest way to get an estimate of abundance with RUV is with MaxN, which is based on the maximum number of individuals of a given species in the field of view at any one time during the recording. We found that maxN was correlated with estimates of abundance from seine netting for only 4 out of 11 species, suggesting that maxN is only a useful indicator of abundance for some species.

Another finding was that RUV was useful for detecting a dramatic population increase of the invasive round goby (Figure 2). In 2022 when we began the RUV study, round goby were detected for the first time north of Peterborough, in the Otonabee River. When invasive species enter new systems, they typically exhibit a population ‘boom’, where they become hyper abundant. Between 2022 and 2023, a boom did occur and was obvious with both RUV and seine netting. This suggests that RUV may be useful for detecting major changes in the abundance of fish, although this is an extreme example of population change.

A round goby from the Otonabee River. This invasive species is quickly spreading through the Kawarthas and as of fall 2024 was caught at Youngs Point, upstream of lock 27 (in Clear Lake).

We concluded that RUV is a promising tool for monitoring fisheries because of its versatility and ease of use. RUV may be especially useful for surveying sensitive and at-risk species, in combination with other techniques, or for community groups. Thanks to members of the Stoney Lake community, namely Bill and Gail Szego and Ralph and Carol Ingleton for supporting this project through donations to the Trent Aquatic Research Program.

Some video samples from the project:

https://youtu.be/YoL0E_CSOas

https://youtu.be/u5ivyAjc8FE

https://youtu.be/X8mcUY4L4Z4

How will warming affect Stoney Lake's sportfish?

by Emily Swick

My name is Emily Swick; I'm a M.Sc. student at Trent University and the newest member of the Stoney Lake Tracking Project. I started at Trent in May 2025 and I’ve spent a lot of time on Stoney this summer and fall! Below you can see a photo of me aboard RV Ingleton helping with our annual receiver download this past summer.

We’ve tagged a wide range of fish species in Stoney Lake, including musky, walleye, smallmouth bass, largemouth bass, yellow perch, black crappie and lake whitefish. While some of our tags just tell us about the movement of the tagged fish around Stoney Lake, other (fancier) tags are equipped with more advanced sensors and collect detailed information on fish acceleration, depth, and even body temperature.

For my project, I get to use this data to answer a few big ecological questions about walleye and smallmouth bass. These fish are both popular sportfish loved by many anglers (including myself) and top predators, so they are important both economically and ecologically. They are thought to differ in their preferred water temperatures; walleye are cool water fish while experts will tell you smallmouth bass do better in warmer water. One of the big challenges in biology is to understand and predict how wild animal populations will respond to climate change. Rising water temperatures affect fish species in different ways. As water temperatures continue to rise, those changing conditions could create “winners” and “losers” in the fish community. We’d expect cool-water species like walleye to lose out, while warmer-water species like smallmouth bass may benefit. However, that’s just a prediction; one we need to test and evaluate using a variety of different types of evidence. Figuring out how fish populations are likely to change in the coming decades can be very useful for fisheries planning and for prioritizing conservation efforts.

For my project, I want to answer two big questions about Stoney Lake walleye and smallmouth bass:

1.    How does water temperature influence fish growth?

2. What water temperatures do fish prefer?

To answer the first question, I will use Bioenergetics modeling. Energy is a currency for all animals, like money is to us. Fish need energy for both the cost of living (like the cost of rent or bills for us) and to grow (this is like their savings).  When fish consume energy through food, this is like their paycheck. If water temperatures get high enough, fish growth decreases because the “cost of living” goes up for the animal (water temperature is like inflation). Having accurate estimates of metabolic costs is important when using bioenergetic models to estimate fish growth. For the fish in Stoney Lake, we can estimate how their metabolic costs vary across space and time for each animal we’ve tagged, using accelerometer tags (our fish “Fitbits”). With these more accurate estimates of fish “living expenses”, I will create models that seek to explain how growth is affected by temperature and by the behavioural strategies used by walleye and smallmouth bass, both in current conditions and under future warming scenarios.

For the second part of my masters project, I will look at the temperature preferences of Stoney Lake walleye and smallmouth bass. Fish are cold-blooded, so their body temperature is the same as the water temperature around them.

Fish can’t regulate their internal body temperature like we can, but they live in an environment with a range of different temperature options. By swimming into shallower or deeper parts of the lake, they can warm up or cool down as needed. Using tags that tell us the depth of the tagged fish, along with the water temperature at that depth, which we record year-round, I will calculate fish body temperature and determine what temperatures these fish are choosing. Knowing these temperatures will allow us to predict how at risk these fish will be as the temperature profiles of our lakes continue to change in the coming decades. 

I am at the early stages of my project and will spend this winter (as most fish scientists do) analysing the tracking data we have for walleye and smallmouth bass in Stoney Lake. Stay tuned for results!