3. Can they survive in fresh water and salt water?
"Zebra mussels have been identified in the lower tidal reaches of the St. Lawrence River. With the living proof of a relative of both the zebra mussel and the quagga mussel, Dreissena rostriformis, which lives in the Caspian Sea, a salt water body, it is quite accurate to say 'Eventual colonization into estuarine and coastal areas of North America cannot be ignored.'(Mills, et al., Amer. Zool., p. 271)." Our own experiments indicate that there is an upper limit of salinity to which zebra mussels can adapt, perhaps one-quarter the strength of sea water, but they certainly seem capable of spreading out of strictly fresh waters.
