• Bigger Bass, Longer Lives: The Rise of Smallmouth Bass in Lake St. Clair

    Lake St. Clair’s smallmouth bass have reached unprecedented sizes in recent decades, and researchers have pinpointed several key drivers behind this growth.

    1. Fish Are Living Longer, Growing Bigger

    A long-term analysis by the Michigan Department of Natural Resources (DNR) reveals a rising trend in smallmouth bass longevity. In the early 1970s, the average age hovered around 4.5 years, but recent data shows it now surpasses 7 years. Since smallmouth bass exhibit indeterminate growth, they continue to grow until death, meaning older fish are naturally larger.

    2. Catch-and-Release Is Paying Off

    The shift toward widespread catch-and-release fishing is a major factor. Angler behavior has dramatically changed: today, more than 95% of smallmouth caught in Lake St. Clair are returned alive. This change has led to lower mortality rates, even after the DNR extended the catch-and-release season to year-round, without increasing population-level mortality

    3. Environmental Protections and Policy Changes

    Improved regulatory safeguards have also played a part:

    • Water quality laws: The Clean Water Act (1972) and Canada Water Act (1970) bolstered water health across the Great Lakes basin, benefiting fish growth and survival.
    • Size limit increase: Michigan raised the minimum keep size for smallmouth bass from 12 inches to 14 inches in 1995, enabling more fish to reach larger sizes before becoming harvestable.

    4. Climate Change Extends Growing Seasons

    Gradually warming water in the Great Lakes region has lengthened the fish growth season. Even a few extra days or weeks each year can significantly affect growth rates over a fish’s lifespan.

    5. Myth vs. Reality: Round Goby’s Role

    The invasive round goby has often been credited for bulking up Michigan’s smallmouth bass, but the science is more complicated.

    SUNY College of Environmental Science and Forestry study (2014) found that smallmouth bass in Lake Ontario showed significant weight gains after gobies became established. The research demonstrated that bass feeding on gobies put on weight more rapidly, creating larger and heavier fish compared to pre-goby populations (Daily Orange).

    Lake Erie research mirrored this trend: gobies quickly became the dominant prey item, making up over 70% of smallmouth diets, with bass aged 2–4 growing 11–15% faster than before.

    Michigan’s long-term data, however, tells a different story. On Lake St. Clair, smallmouth were already living longer and growing larger before gobies arrived in the 1990s. The Michigan DNR reports that bass growth trends remained consistent both before and after the goby invasion, suggesting cleaner water, regulation changes, catch-and-release practices, and longer growing seasons are the primary drivers.

    Caution for young fish: Some research indicates gobies can actually compete with juvenile bass for habitat and food, sometimes displacing them and slowing early growth

    6. Record-Topping Bass in the Spotlight

    Recent tournaments underscore the trend. At the 2025 Bassmaster Elite held on Lake St. Clair, anglers reported catching multiple “trophy-length” smallmouth bass, fish over 20 inches long, typically weighing around six pounds. The lake has even earned national acclaim, ranking #10 in Bassmaster Magazine’s 2025 list of top U.S. bass lakes.

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