The recent confirmation of round gobies in Lake Winnebago marks a significant development for our interconnected waterway system, including Little Lake Butte des Morts (LLBDM). As residents and stakeholders of LLBDM, it’s important to understand both the current situation and our lake’s unique role in this ongoing invasive species challenge.
The Current Situation
On June 2, 2025, an angler caught the first confirmed round goby in Lake Winnebago at the Bowen Street Fishing Pier in Oshkosh. Since then, the Wisconsin Department of Natural Resources (DNR) has confirmed a total of 18 round gobies in Lake Winnebago, with additional fish caught by both anglers and DNR sampling efforts in August and September 2025.
This discovery is particularly significant because it represents the first time round gobies have crossed from Little Lake Butte des Morts into Lake Winnebago proper, despite protective measures that have been in place for a decade.
Little Lake Butte des Morts: The First Line of Defense
Our lake has been ground zero for round goby management efforts since August 2015, when an angler first reported catching a round goby immediately below the Neenah Dam. This initial discovery triggered an immediate response that changed navigation on our waterways permanently.
Following the 2015 discovery in LLBDM, the Fox River Navigational System Authority (FRNSA) voluntarily closed the Menasha Lock at the request of the DNR to prevent further upstream spread into the Lake Winnebago system. This closure has remained in effect for nearly 10 years, serving as a critical barrier against further invasion.
The Bigger Picture
Round gobies are native to the Black and Caspian Seas and were first introduced to the Great Lakes through ballast water in 1990. These aggressive, territorial fish pose several threats to our native fish populations:
- Competition for habitat: They outcompete native bottom-dwelling fish for space and food
- Predation on fish eggs: They consume eggs of valuable sport fish like walleye and bass
- Rapid reproduction: They can reproduce up to six times per season, leading to explosive population growth
- Bait-stealing nuisance: They create frustrating fishing experiences for anglers
In Little Lake Butte des Morts, round gobies have established a significant population over the past decade. However, recent DNR surveys indicate that their impacts on native fish populations have been less dramatic than initially feared, with no significant declines detected in panfish or game fish species during assessments.
Economic Implications
The presence of round gobies affects our region’s economy in multiple ways:
- Recreational fishing impact: Fishing contributes approximately $234 million annually to the local economy according to a 2006 University of Wisconsin-Extension survey
- Navigation costs: The closure of locks has economic consequences, with a 2017 study estimating annual economic output impacts of $4.3 million to $29 million depending on lock operations
Current Response Efforts
The DNR has activated comprehensive monitoring and potential control measures:
Intensive Monitoring
The agency is conducting targeted sampling throughout the Winnebago System to determine the extent of the invasion. On September 25, 2025, the DNR and local fishing groups organized a “round goby blitz” with volunteers fishing at multiple locations including Oshkosh, Neenah, Menasha, and High Cliff State Park.
Potential Control Measures
The DNR is considering the use of rotenone, a naturally derived fish-killing agent, within contained areas if the gobies remain localized near the Bowen Street Fishing Pier. However, this option would only be viable if the population hasn’t spread throughout the lake system.
Continued Barrier Protection
Despite the breakthrough into Lake Winnebago, there are no plans to reopen the Menasha Lock or Neenah-Menasha dam, as these barriers remain essential for preventing further spread and managing the existing population.
What You Can Do
As LLBDM residents and users, you can help with ongoing monitoring efforts:
- Report sightings: Use the DNR’s online Round Goby Reporting Tool to report any suspected round goby catches in Lake Winnebago waters
- Proper disposal: Kill any round gobies caught and bring them to a DNR service center for verification
- Prevention practices: Clean boats and equipment thoroughly when moving between water bodies
- Stay informed: Monitor updates from the DNR and local watershed organizations
Important note: Round gobies captured in Little Lake Butte des Morts do not need to be reported, as this population is already established and well-documented.
Looking Forward
The confirmation of round gobies in Lake Winnebago represents a new chapter in invasive species management for our region. While concerning, the situation in Little Lake Butte des Morts has shown that established round goby populations don’t necessarily lead to catastrophic impacts on native fish communities.
The focus now shifts to assessment and potential early intervention while the Lake Winnebago population appears localized. The next few months will be critical in determining whether containment efforts can succeed or if Lake Winnebago will join Little Lake Butte des Morts in hosting an established round goby population.
As we’ve learned from our decade of experience with round gobies in LLBDM, careful monitoring and adaptive management remain our best tools for protecting the ecological and economic value of our interconnected waterway system.
Sources:
- Wisconsin Public Radio – DNR steps up monitoring
- FOX 11 – Round goby presence prompts DNR response
- Fox-Wolf Watershed Alliance – Round Goby Update
- Milwaukee Journal Sentinel – Invasive round gobies discovered
- DNR – Goby Reporting Information
- WTAQ – Round goby monitoring intensifies
For more information and to report round goby sightings, visit the DNR’s online Round Goby Reporting Tool.