The rise and fall of green sunfish in Gilmore Creek
2014
Hulett, Cassandra C. | Frechette, Rachel A. | Cochran, Philip A.
We examined the dynamics of green sunfish (Lepomis cyanellus) in Gilmore Creek, a coldwater trout stream in southeastern Minnesota, over two time scales. On a historical scale, green sunfish occurred in the creek with other warmwater fishes after deforestation and poor farming practices in the late 1800s and early 1900s resulted in higher water temperatures and other habitat degradation. Reforestation and improved land management led to a restored trout fishery by the 1970s and 1980s. Since then, green sunfish have been known to invade the creek from downstream Boller Lake during high water events in late summer or early fall. After such an invasion event in 2010, catches of green sunfish declined exponentially over the subsequent months. Available evidence suggests that green sunfish have little predatory impact on brown trout because few sunfish remain in the creek by late fall when trout lay their eggs, and even fewer sunfish are present by spring when trout eggs hatch.
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