Presentations include

Mussel squeeze: dissolved oxygen and temperature can “squeeze” zebra mussels out of invaded reservoirs by Rich Miller and Crysta Gantz with Portland State University, Portland, OR

Survivorship and distribution of zebra mussels within a waterbody are thought to be influenced by temperature and dissolved oxygen conditions, but detailed information to confirm the importance of these environmental controls is necessary to inform management efforts. We measured planktonic zebra mussel veliger density and adult survivorship in San Justo Reservoir in central California to determine distribution and timing of spawning in relation to temperature and dissolved oxygen throughout winter, spring, and summer. We found seasonal patterns in adult survivorship, with high mortality late in the summer and higher than expected survivorship during the spring when dissolved oxygen concentrations were approximately 1 mg/L. Veliger abundance peaked several meters above the thermocline from June to August. Dissolved oxygen concentrations limited veliger distribution, with few to no veligers collected in the anoxic hypolimnion. Veliger settlement out of the water column appears to be possible in San Justo Reservoir at any time of year.

Dreissena in the Great Lakes: what have we learned in 35 years of invasion by Alexander Karatayev with SUNY Buffalo State, Buffalo, NY

This presentation summarizes over 30 years of research on zebra and quagga mussels in the Laurentian Great Lakes and compared with data from European and North American inland lakes. Invasion dynamics, growth, and reproduction of dreissenids in the Great Lakes are governed by lake morphometry. The abundance of commercially important fishes declined as a result of the dramatic decrease in their main food deep water amphipods Diporeia, which has been outcompeted by exotic mussels. However, the introduction of round goby into the Great Lakes in the 1990s provided an important link between dreissenids and commercially and recreationally valuable fish species, increasing their productivity.