Introduced to the Laurentian Great Lakes via ballast water from trans-Atlantic voyages by 1990, the round goby (Neogobius melanostomus) joined the list of invasive species in the Duluth-Superior harbor in 1995. The round goby is a relatively small and aggressive benthic fish, which directly competes with native species for resources and habitat. One of the reasons for the round goby’s success as an invader is its reproductive strategy, which includes multiple spawning events within the spawning season and a nest-guarding male that uses vocalizations to attract females. In addition, round gobies will prey upon the eggs of native fish, such as lake trout, Salvelinus namaycush (Chotkowski and Mardsen 1999, Jonas et al. 2005, Fitzsimons et al. 2006), lake sturgeon, Acipenser fulvescens (Nichols et al. 2003) and smallmouth bass, Micropterus dolomieu (Steinhart et al. 2004). The round gobies’ aggressive behavior and reproductive strategy, has led to direct competition with native species and has enabled them to become a major component of the benthic community in the Laurentian Great Lakes.
Fortunately, the goby’s vocalizations can be used to attract females for removal, decreasing reproductive success and releasing pressure on native fish. Preliminary trials conducted in August of 2010, showed female phonotaxis to low frequency stimuli. However the number of female gobies entering the trap (standard wire mesh minnow trap) needs to be increased for this new method to be practical. The objective of this project was to develop a fish trap that would increase the capture and retention rate of the round goby.