Citizen Science reveals unexpected finding!

Volunteers from Trout Unlimited Canada – Northern Lights Fly Fishers Chapter conducted a “citizen science” project to study walleye in Jackfish Lake, Alberta. The study took place during the open-water season of 2021. We assumed that big fish (>50cm) would be more vulnerable to angling because they consume more food.  The objective of the project was to estimate the vulnerability of different size classes of walleye to capture by angling, and potentially use this information to influence angling regulations.

Detailed (size-related) data is necessary to help determine options for regulations for Walleye, and to assess the effectiveness of slot-size limits to protect the long-term sustainability of the fishery. Additionally, promoting Walleye angling in high-quality, trophy fisheries will ignite additional angler interest in Walleye fishing as a non-consumptive activity providing greater security for the walleye population and fishery.

Volunteers worked with biologists from Alberta Environment and Parks.  Fish were captured using traditional angling techniques and their fins were marked as a means of identifying fish that were previously caught.  A PIT tag (Passive Integrated Transponder) was inserted into larger fish so that upon recapture they could be scanned with a tag reader to determine the number of times that fish had been caught.

Nearly 200 fish were re-captured during the study, some as many as four times over the summer.  Analysis of the recapture data showed that vulnerability to angling did not increase with walleye size.  Specifically, walleye larger than 50 cm did not show higher vulnerability than walleye 40 to 50 cm.   Estimates on the total fish population in the lake and the number of anglers were also established as part of the study.

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Volunteer Angler with a nice Walleye

The findings are being used by fisheries biologists to evaluate and establish walleye regulations involving harvest and size limits, and to maintain sustainable and quality walleye fisheries. One fisheries biologist commented “this is important data and will be used for decades in our walleye science.”  The information collected is important to designing effective regulations to maintain these very popular and demonstrably sensitive fisheries. 

A startling finding of the study can be summarized in this conclusion:

Based on estimated rod and and walleye populations – If each angler harvested only 1 walleye, the entire population could be caught in one year. This simple and stark example illustrates the necessity for precautionary management of this walleye fishery, and perhaps other similar Alberta walleye fisheries.  

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Volunteer Anglers in action

This project was financially supported by the Alberta Conservation Association.