Zebra mussels as a potential tool in the restoration of eutrophic shallow lakes, dominated by toxic cyanobacteria

Data on grazing, survival and microcystin uptake of zebra mussels (Dreissena polymorpha Pallas), exposed to toxic cyanobacteria, were collected in a four year study to examine if zebra mussels may be exploited as a biomanipulation tool for the restoration of eutrophied shallow lakes in the Netherlands.

It was shown that adult zebra mussels can use cyanobacteria as food in the water column, irrespective of the size, shape, form and toxicity of these phytoplankton species. Mussels even seemed to prefer cyanobacteria over other phytoplankton groups and detritus. Toxic cyanobacteria affected the survival of the larvae but not that of the adult mussels. Finally, zebra mussels assimilated the cyanobacterial toxins but only to a limited extend. The toxin concentrations in mussels were not nearly as high as those found in other aquatic organisms. Even these low levels however, are still high enough to produce liver damage in diving ducks, the main mussel predators in the Netherlands. Overall, the findings of this study provide support for the potential use of zebra mussels in the restoration of shallow lakes in the Netherlands from eutrophication.