Tagging methods for the round goby (Neogobius melanostomus)

The Pound goby (Neogobius melanostomus) was first discovered in North America in the St. Clair River in 1990 and has since spread throughout the Great Lakes. In 1993 they were found in the Calumet River which presently drains from southern Lake Michigan, and because of lock and dams downstream have begun to move through the Chicago canal system toward the Illinois River. Information about the routes, vectors, and rates of movement of round gobies would be valuable in predicting their potential spread through river and lake systems. In this study various methods for marking round gobies to track their movements were examined. Two types of external tags, four subcutaneously injected liquid dyes, and one subcutaneously injected Eater base paint were tested. Both laboratory and field studies were performed with the tags to determine tag-induced mortality and tag loss rates. Laboratory-tagged fish were held for up to Id weeks; field-tagged fish were recaptured up to 218 d after tagging. The optimal tag in terms of ease of use, high visibility, retention, and low mortality or damage to fish was injected latex paint. The best technique for individually marking fish was use of the Floy anchor tag; fish with this tag had no tag loss but experienced 50% mortality. The movement of round gobies along the shoreline at Calumet Park in South Chicago, Illinois was also examined. Nineteen (6%) of 308 tagged fish were recovered. All recaptured fish were caught within 67 m of the tagging site, except for a single fish caught 218 d after tagging, approximately 2 km from the ragging site.