Bass fishing tournaments are a fixture on Ontario lakes every summer — but what actually happens to the fish after weigh-in? An RLEF-supported study published in the North American Journal of Fisheries Management tracked largemouth and smallmouth bass on Big Rideau Lake across three tournaments in 2017, and the findings are worth understanding for anyone who fishes, cottages, or cares about the health of these lakes.
The Setup
Researchers from Carleton University acoustically tagged 118 tournament-caught bass across three events spanning early season (June), mid-season (August), and late season (October), then tracked their movements using an underwater receiver array for two years. The key questions: how long do fish pile up near the weigh-in site, and do they eventually make it back to the main lake?
Fish Pile Up — But Not for Long
All detected fish did eventually leave the release site, but short-term stockpiling occurred following all tournaments. The two species behaved differently. Smallmouth bass dispersed within a day of release across all seasons, while largemouth bass exposed to the mid-season tournament took a median of 4.6 days to leave — and some individuals lingered for over 40 days.
The timing matters. Fish exposed to the mid-season tournament, when surface water temperatures reached 24–26°C, tended to stockpile longest — likely because higher temperatures increase physiological stress and limit exercise performance in fish.
Getting Home Takes Much Longer
Leaving the release site is one thing. Returning to the main basin is another. Half of detected largemouth bass took between 3.6 and 7.8 months to reach the main basin depending on tournament timing, and some took up to 18.5 months. Smallmouth bass fared better overall, with half returning within one to three months — though late-season fish took the longest, likely due to the added challenge of displacement during fall pre-wintering movements.
Importantly, these return times represent arrival at the lake entrance, not the original capture site — meaning actual return times are likely longer than reported.
What It Means for Tournament Practices
The authors note that displacing trophy-sized fish — which are precisely the individuals tournaments target — to a common release site for months at a time may function as a form of effective removal from main-lake populations, in ways managers may not fully account for.
The paper recommends moving toward catch-weigh-release formats conducted at the boat, which would eliminate displacement effects entirely and reduce conflicts among lake users. Where shore-based weigh-ins are retained, the authors suggest release locations be chosen to offer suitable recovery habitat for both species, and that catch-weigh-release formats be adopted adaptively during periods of high water temperature.
A Local Study with Broader Implications
This research was conducted on Big Rideau Lake with partial funding from the Rideau Lakes Environmental Foundation and the Big Rideau Lake Association — making it directly relevant to the communities and anglers who use these waters. The science doesn’t call for ending tournaments, but it does provide a clearer picture of their ecological footprint and a practical path toward reducing it.
Alice E. I. Abrams, A. J. Zolderdo, Elodie J. I. Lédée, Michael J. Lawrence, Peter E. Holder, Steven J. Cooke, “Dispersal Patterns of Largemouth Bass and Smallmouth Bass Following Early‐, Mid‐, and Late‐Season Fishing Tournaments in an Eastern Ontario Lake”, North American Journal of Fisheries Management, Volume 41, Issue 5, October 2021, Pages 1454–1464, https://doi.org/10.1002/nafm.10664 Full Text Available as PDF.