By Kyrmyzy Turebayeva
A new study based on data from competitive angling events in the Great Lakes found that more than 20% of black bass weighed-in at these events are over 10 years old, with at least one individual reaching its early 20s.
Researchers from Queen’s University in Kingston, Ontario, studied populations of largemouth bass (Micropterus nigricans) and smallmouth bass (Micropterus dolomieu) – both members of a taxonomic group known as black bass – in the eastern part of Lake Ontario and the St. Lawrence River.
The study drew on biological data collected from competitive catch-and-release bass tournaments, which have become a rapidly expanding component of Great Lakes fisheries.
“The Great Lakes are enormous and highly dynamic ecosystems, which can make it difficult to sample black bass using traditional scientific methods,” said Connor Elliott, a researcher at Queen’s University and the study’s lead author.
“Competitive angling events provide us with a unique opportunity because tournament anglers consistently target the largest adult fish — individuals that are rarely captured through standard sampling approaches.”
Bass tournaments in eastern Lake Ontario and the St. Lawrence River are conducted under catch-and-release rules, with the goal of returning fish alive to the water so they can continue contributing to the population and be caught again in the future.
“Even with modern fish-care practices, a small amount of incidental mortality still occurs during tournaments,” Elliott explained.
“These losses may happen during capture, while fish are held in livewells prior to weigh-in, or during the weigh-in process itself. From a scientific perspective, these rare cases provide valuable biological information about the largest and oldest black bass in the system.”
One of the most unexpected findings came from the analysis of otoliths – tiny crystals in the inner ear used to determine a fish’s age.
Researchers discovered that bass caught during tournaments were far older than expected.
The average age was 8.5 years, more than 20% of the fish were over a decade old and the oldest collected was 21.
According to the researchers, the findings have important implications for fisheries management.
In the Great Lakes, black bass can take nearly a decade to reach tournament size, meaning that management decisions made today may not affect population structure until many years later.
According to the Great Lakes Fishery Commission, the Great Lakes fishery generates more than $5.1 billion annually. The resource is jointly managed by the United States and Canada, with lake-specific committees coordinating harvest regulations, stocking programs and habitat improvement measures across shared waters.
Environmental monitoring confirms that black bass populations in the region remain stable.
The study also found that smallmouth bass are generally heavier and longer than largemouth bass in the Great Lakes, which has led tournament anglers to increasingly focus on smallmouth bass.
Historically, largemouth bass were considered the larger species in most water bodies and were therefore the primary focus of tournaments.
In the Great Lakes, however, the situation has changed — smallmouth bass grow faster and reach larger sizes.
This shift is closely linked to changes in diet and habitat. A major factor is the round goby (Neogobius melanostomus), an invasive fish species that has become a dominant prey item for smallmouth bass.
In a separate 2017 study, the same research group used genetic analysis of stomach contents to show that a large portion of the smallmouth bass diet now consists of round gobies.
“Largemouth bass remain more generalist predators with a broader diet,” Elliott said.
“Smallmouth bass, however, increasingly specialize on round gobies because their habitats overlap so strongly. Gobies are now widespread and extremely abundant in the Great Lakes, effectively providing an unlimited food source.”
As a result, smallmouth bass in the region are often heavier than largemouth bass of the same length, making them especially attractive targets in competitive fisheries.
The growing focus on larger, older smallmouth bass has heightened concerns about fish survival during tournaments. In response, tournament organizers may use increasingly strict fish-care practices.
These include improved aeration systems at the weigh-ins, standardized handling and holding procedures, and angler training focused on minimizing stress and injury to fish.
“Smallmouth bass conservation requires especially careful handling in the Great Lakes. There are region-specific guidelines designed for these species, and following them is critical to maintaining sustainable tournaments and healthy black bass populations,” said Elliott.
According to the researchers, these efforts are already showing results.
Tournament organizers who follow science-based handling guidelines have helped push survival rates so high that, in some cases, scientists struggle to collect enough incidental mortalities for long-term monitoring, a limitation for research, but a clear ecological success.