An invasive fish known as the green sunfish has been confirmed in the Piscataquog River downstream from the Weare Reservoir, also known as Horace Lake, and at Waukewan Lake. This is an expansion of the range: In 2022, biologists at the NH Department of Environmental Services discovered three specimens in the Little Sugar River in Charlestown.
Green sunfish are a concern because they compete for habitat and food resources with the state’s native sunfish. Relatives of native fish like the largemouth bass, bluegill and pumpkinseed, they can be found in a variety of habitats and tolerate a wide range of environmental conditions.
Their large mouth enables them to consume a wider variety of prey than native pumpkinseed or redbreast sunfish, and this advantage may allow them to outcompete native species for food. They are now found in all 48 contiguous states.
Green sunfish are a popular aquarium fish often kept by hobbyists. This is likely the reason they have made their way into Granite State waters. Releasing any aquarium fish into the natural environment is illegal and a threat to a variety of native wildlife.
The state tells anglers that if they suspect they have caught a green sunfish, not to release it. “Humanely terminate the fish, being careful to preserve its coloration and identifying characteristics. Take a clear photo, record the location, and email your findings to email@example.com,” New Hampshire Fish and Game said in a press release.
To learn more about identifying green sunfish visit Lepomis_cyanellus.pdf (raritanheadwaters.org).