PARENT SESSION
Poster Session #4: Invasions.
Monday, August 6, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Round goby effects in Lake Erie: short-term and long-term projections.

Miner, Jeffrey¹, Bombich, Michael¹, Kireta, Amy¹, Lowe, Rex¹, ¹

ABSTRACT- The round goby Neogobius melanostomus invaded the Great Lakes almost a decade ago, subsequent to the invasion by one of its primary prey resources, zebra mussels Dreissena polymorpha. In a series of laboratory and field experiments, we have quantified the short-term effects of round gobies on both zebra mussels and the invertebrate community associated with zebra mussels. When the population of zebra mussels is dominated by small individuals (< 15-mm shell length), we found that round gobies could consume over 60% of the zebra mussels in one year and correspondingly suppress other macroinvertebrates. When zebra mussels are large, and thus attain a size refuge from predation by round gobies, we find that the zebra mussel population filtration capacity is not substantially reduced and the integrity of the mussel bed remains, allowing the macroinvertebrate community to be only marginally affected, even at round goby densities as high as 12 per meter square. However, the near elimination of small mussels recruiting to the interstices of mussel beds suggests that if round gobies maintain sufficient densities to suppress zebra mussel recruitment, densities of adult zebra mussels will begin to decline.

KEY WORDS: Invasion, Great Lakes, Round goby, Zebra mussel