Meeting Abstract
The round goby (Neogobius melanostomus) is an invasive benthic fish first introduced to the Laurentian Great Lakes in 1990. The round goby has negatively impacted native fishes through high fecundity, aggressive interactions, and egg predation. The latter effect may be leading to a decline in the reproductive success of a newly established breeding population of lake sturgeon (Acipenser fulvescens). While complete eradication of the round goby is not currently possible, intensive trapping in designated areas during spawning seasons could lead to reduced egg predation. A 100 meter stretch of shoreline within the Duluth Superior Harbor was selected for trapping over the duration of the round goby breeding period (June to October). Minnow traps were baited with 400 g of fresh fish, and round gobies were removed from the experimental area every 48 hours. Control traps were deployed once a week, with captured gobies tagged with alphanumeric tags before release. Consistent removal reduced the catch per unit effort of round gobies by 38% compared to control areas outside the collection area. Perhaps more importantly, there were extended periods with no round gobies caught in the experimental traps. However, there was no difference in the size or gender of round gobies caught in the two areas. In addition, 69% of tagged gobies (n=23) were recaptured at the initial release site in the control areas, suggesting high site affinity. Therefore, it is unclear where the repopulating round gobies originated. Future experiments will examine different bait to increase trapping efficacy and look into how often trapping should be conducted to maximize population reduction.
