Tag, You're It! 153 new fish join our tracking project

This spring, our team led by PhD student Amber Fedus, along with Dr. Jake Brownscombe and Kurt Smith from DFO, worked long days over many weeks to put a whopping 153 new transmitters into fish on Stoney Lake. We are now up to 215 fish (!!) that have been implanted with transmitters. The overall tally includes 79 walleye, 69 smallmouth bass, 36 yellow perch, 23 black crappie, and 8 muskellunge. It was a huge team effort; nearly every member of the Raby Lab spent time in the field helping Amber, Jake, and Kurt. Special thanks to Brent Whetung for catching walleye for us, to Ben and Viamede Resort for use of their docks, and to Ed Paleczny and Jackie Ouellette who also let us use their property.

(Left) The research team from this spring.

The tagging season wasn’t without its challenges. Many long days and nights of angling and electrofishing, often to catch very few of our target species. A heatwave in May surged water temperatures, not an ideal condition for fish survival. We adapted by tagging the fish at night when it was cooler, using cold water pumped from deep.

We notably struggled to locate muskies, known as the 'fish of 10,000 casts'. Nevertheless, we tagged six more, taking our total to eight. Muskies Canada Inc. and the Kawartha Lakes Chapter have generously contributed a combined $6500 for purchasing transmitters. They also arranged a muskie fishing day for us (to catch fish for tagging), which, due to the heatwave, had to be canceled to avoid risk to the muskies. We plan to reschedule it for October, with the help of volunteer anglers and will further aim to catch more muskies next spring during their spawning period.

A couple of individuals have reported finding tagged fish – an encouraging sign. The walleye bear a conspicuous external loop tag on their back (see video), marked with my contact number and a unique ID. Other species don't have external tags, but a recent tagging will reveal an incision site on their underside. The tagged fish are safe to consume and if a transmitter is returned, we can repurpose it for another fish. If you come across someone unsure about what to do with a tagged fish, don't hesitate to direct them to me at grahamraby@trentu.ca.

This week, we've begun extracting underwater receivers to gather fish detection data, a process that will span a couple weeks. After a quick battery change, we re-deploy the receivers in their original spots, concealed 6+ feet below the surface. We'll then start the demanding task of organizing millions of data points and beginning to decipher the activities of our aquatic subjects. Keep an eye on this space for more updates!

Complementing fish movement data with water chemistry

By Miracle Denga, Undergraduate Honours Thesis Research Student, Department of Biology, Trent U Limnologists have always been interested in studying the vertical patterns of lake variables like temperature and dissolved oxygen. Thanks to recent improvements in the sensors used for water monitoring, we can now look at the vertical patterns of many variables in water at incredibly high resolution. A vertical profiler (we use the RBRmaestro³ Multi-Channel Logger, as seen in the pictures below) is a sensing tool that measures different lake variables as you lower the instrument into the lake, including dissolved oxygen, temperature, chlorophyll a, pressure, and several others. These advanced vertical profilers can take eight measurements of each of the above variables per second, creating an extremely detailed image of how lake conditions vary with depth. The data that a profile generates are incredibly useful – they can tell us the different phases the lake is in; for example, whether it's stratified or well mixed. The profiler data can also show us the amount of oxygen available to creatures at the bottom of the lake and provide an estimate of how much phytoplankton is in the water column. The information gained with a profile can give us baselines of what a lake should look like and help understand the factors that cause lakes to change (for better or worse). Ultimately, these sorts of data can be useful for developing best practices for lake management which are undeniably of benefit to stakeholders and to the creatures living in the lake. Below you can see some of the data we collected on Stoney Lake this May.

About me: I am an undergraduate student at Trent University doing my honour’s thesis in Dr. Marguerite Xenopoulos’ Aquatic Ecology Lab. I am investigating the factors affecting differences in the rates of deep-water oxygen depletion in the Kawartha Lakes, which involves taking monthly vertical profiles from a selection of Kawartha Lakes over the summer. This work started in May and Stoney Lake is one of the lakes we are focusing on. Stoney was profiled intensely once last summer with the intent of creating a 3D distribution of the lake variables listed above (done by Drs. Raby, Frost, and Pearce, see link). This year, I will continue sampling Stoney throughout the summer and fall. The data will be paired with data on fish tracking to see what drives fish movements and get a better sense of the dynamics of water quality in the system.

(Above) Deploying the RBR profiler in Stoney Lake on May 12.

Spring update 2023

Hi folks,

Happy spring. I hope you’re enjoying the weather and making plans to spend some time on the water soon (either on Stoney Lake or elsewhere).

I have lots of updates but I’m going to just focus on a few things for this first post of the season and save the rest for later.

This winter, we received more generous support from the Szego and Ingleton families for the project, primarily to fund the purchase of acoustic transmitters to put into fish. Their generosity means the project will continue to grow this year as we had hoped.

We also received a donation from the Kawartha Lakes Chapter of Muskies Canada, and a small research grant from Muskies Canada. Those funds have been used to purchase transmitters to put into muskies, which was always our hope with this project. Muskies Canada has a strong history of supporting research. Fun fact: muskie anglers rarely harvest any of their fish (the release rates are ~100%), and the fish that are released have very high survival if best practices for angling are used (source).

In the end, because of the donations above, and because of further support from our DFO partner (Dr. Jake Brownscombe) and other grants I hold at Trent, we have 173 transmitters in hand for 2023. The plan is to allocate those tags for: walleye (60), smallmouth bass (44), muskellunge (20), yellow perch (24), and black crappie (25). We’ve already tagged 19 walleye this year (41 to go). Muskies (‘the fish of 10,000 casts’) will be a particular challenge, but we’re hoping our friends in the Kawartha Lakes Chapter of Muskies Canada will help a bit on that front.

To that end, we’ll be on the lake over the next couple weeks trying to capture and tag as many fish as possible before the water gets too warm (we tend to avoid doing surgeries on fish at about 21°C or higher). If you or anyone you know is going to be on the water fishing and would like to help catch fish for the project (especially on weekdays), get in touch with me. grahamraby@trentu.ca

Graham