Meeting Abstract

19.3  Jan. 5  A comparative study of sensory physiology and competitive interactions of the invasive round goby with three native species: slimy sculpin, spoonhead sculpin, and logperch BERGSTROM, MA*; MENSINGER, AF; Univ. of Minnesota Duluth; Univ. of Minnesota Duluth berg1102@d.umn.edu

Population declines in native benthic fish populations across the Great Lakes have been attributed to the round goby (Neogobius melanostomus) invasion. Few studies have performed both behavioral and physiological experiments to characterize the ability of round gobies to displace native species. Round gobies appear to be more aggressive, mature more quickly, have higher fecundity than most native species, and have been documented to negatively impact the mottled sculpin (Cottus bairdii) (Janssen and Jude 2001). Other benthic species potentially affected by round gobies due to diet overlap or interspecific competition include the slimy sculpin (Cottus cognatus), spoonhead sculpin (Cottus ricei), and logperch (Percina caprodes). Experiments were conducted over three weeks with one round goby and one or two natives in a simulated stream. Native fish were able to maintain or slightly increase weight in the absence of the goby. Although slimy sculpins were able to maintain this trend after the additional of the goby, spoonhead sculpins and logperch experienced significant weight loss when combined with a round goby. Concurrent predator-prey studies indicated that round gobies detected prey at greater distances in the dark than native fish, suggesting greater range of its mechanosensory lateral line. However both sculpin species exhibited longer reactive distances than the round goby and logperch during daytime conditions. The goby�s ability to outcompete native fish for limited food combined with its nocturnal sensory advantage provide distinct advantages that have contributed to its successful invasion.