Influence of Environmental Factors on Zebra Mussel Population Expansion in Lake Champlain, 1994–2010

Marsden, J.E., Stangel, P., & Shambaugh, A. (2013) Influence of Environmental Factors on Zebra Mussel Population Expansion in Lake Champlain, 1994–2010. In T.F. Nalepa & D.W. Schloesser (Eds.), Quagga and Zebra Mussels: Biology, Impacts, and Control, Second Edition (pp. 33-54). Boca Raton, FL: CRC Press.

The spread of zebra mussels is facilitated by currents and human traffic and may be limited by temperature, calcium availability, and productivity. Lake Champlain is an interesting system for examining factors that affect spread of zebra mussels, as the lake has a complex structure consisting of bays separated by islands and causeways, water flows from south to north, temperature and calcium concentrations decrease from south to north, and productivity is highest in southern areas of the lake and in regions of the Northeast Arm. Zebra mussels were first discovered in Lake Champlain in 1993 and spread to all regions of the lake by 1996. Monitoring was conducted at 24 stations lake-wide between 1994 and 2010 to track the spread of zebra mussels and monitor water-quality parameters and plankton densities. Spatial expansion of zebra mussels in the lake was largely mediated by currents and barriers to flow. Veliger production, density, and recruitment of juveniles appear to be most strongly associated with productivity. Correlation of zebra mussel colonization rate and densities with calcium concentrations is confounded by currents and by temperature and productivity gradients. Colonization has been slowest and remains at lowest densities, in areas furthest from the initial invasion that have the lowest calcium concentrations, lowest annual mean temperatures, and lowest productivity measures. Local areas of high productivity within the low-density basins have high densities of mussels. Water clarity has increased in some areas of the lake, abundance of some benthic invertebrates has increased locally, and unionid mussels have declined, but other changes in the lake that might be attributable to zebra mussels, such as changes in productivity, have not occurred.