OSHKOSH, Wis. - As ice fishing heats up on the Lake Winnebago System, the Wisconsin Department of Natural Resources is urging anglers to report the incidental catch of round gobies in the lower Fox River above the Rapide Croche Dam, in Little Lake Butte des Morts and in Lake Winnebago.
Round gobies are destructive aquatic invaders and were discovered in Little Lake Butte des Morts immediately below the Neenah Dam in August 2015. The aggressive fish out-compete some native species and pose a significant threat to the ecology of the Winnebago System.
Kendall Kamke, DNR Oshkosh fisheries team supervisor, said anglers in other areas where gobies are well-established occasionally catch them while ice fishing. DNR continues to encourage Winnebago area anglers to report any catches through an online survey tool at http://dnr.wi.gov/u/?q=132 to help determine the extent of gobies in the region and develop a management strategy. The online tool also allows anglers to upload goby photos.
Gobies are on the Chapter NR 40 list as a restricted invasive species and it is illegal to possess, transport, transfer or introduce live gobies, including using them as bait. When gobies are caught, they should be killed and removed from the waterbody.
Anglers who catch a goby on Lake Winnebago, other parts of the Winnebago System or the lower Fox River below the Neenah and Menasha dams are encouraged to kill the fish and freeze it before bringing the specimen to the DNR Oshkosh office, 625 E. County Road Y, Suite 700, Oshkosh, Wis., 54901-9731. The office is open from 8:30 a.m. to 4 p.m. Monday through Friday.
"We are extremely grateful for the assistance we've received from anglers who have taken the time to notify us when they catch gobies," Kamke said. "When we receive reports from the specific areas of interest, we do contact the anglers to get more details and confirm their catch. These are fish that nobody wants to catch, but when they do, we appreciate being able to follow up with the anglers as we work to determine how widespread the goby population is."
To date, no gobies have been found above the Menasha lock, which remains closed thanks to cooperation with the Fox River Navigational System Authority. The authority operates a system of locks and monitors for aquatic invasive species within the lock system.
"Fishing and recreational and commercial navigation all make significant contributions to the local economy, not to mention the incredible quality of life we enjoy in Wisconsin. We recognize the importance to do our part to prevent the spread of gobies," said Bob Stark, chief executive officer of the authority. "At the same time, we are working cooperatively with DNR on possible solutions to the navigational challenge posed by the lock's closure. In October, we treated the Menasha lock with the chemical rotenone to kill any aquatic hitchhikers and allow passage of some larger boats back into Lake Winnebago. We are working with DNR to develop longer-term strategies."
Following open water season efforts to capture gobies through electroshocking, trapping, trawling and netting, DNR intends to use major ice fishing events and the upcoming sturgeon spearing season to continue angler education efforts and conduct additional surveys. During sturgeon spearing season, which this year begins on February 13, fisheries biologists will be collecting and dissecting 80 sturgeon stomachs for diet analysis.
"At this time of year, we can usually confidently identify forage items within the foreguts of sturgeon because digestion of prey items in this location hasn't yet started," said Ryan Koenigs, DNR Lake Winnebago sturgeon biologist.
Since round gobies were first discovered in the St. Clair River in 1990, the bottom-dwellers have spread rapidly into most areas of the Great Lakes including Lake Michigan. Round gobies can survive even in poor quality water and displace native fish by eating their eggs and young, taking over optimal habitat and spawning multiple times per season, which gives them a competitive advantage.
Kamke said there is no way to determine how the gobies arrived in the channel below the Neenah dam, which opens into Little Lake Butte des Morts. Gobies can be identified by a single, scallop-shaped pelvic fin on the belly of the fish, a black spot on the front dorsal fin, frog-like raised eyes and thick lips. No other native Great Lakes fish possess the single pelvic fin. They range in size from 3 to 6 inches and have a mottled gray appearance.
In addition to submitting reports via the mobile friendly survey tool, anglers may visit the DNR Facebook page or website, DNR.wi.gov and search "goby" to file a report. Anglers are reminded that live bait and water from bait buckets should always be disposed of away from the water's edge.