Not wanting to hijack this post but here is one observation from Lake Champlain in New York…
Fish predation on zebra mussels is regularly occurring at a number of sites throughout Lake Champlain. Sheepshead, pumpkinseed, yellow perch, and rock bass have all learned to recognize zebra mussels as food. More than 50% of the pumpkinseeds and about 40% of the sheepshead collected had zebra mussels in their guts, suggesting that these fish are commonly consuming zebra mussels as prey. About 15% of the yellow perch collected contained zebra mussels in their guts. The large numbers of pumpkinseed, sheepshead, and yellow perch in the lake suggest that these fish have the potential to significantly reduce the abundance of zebra mussels over time. We also suspect that we have not yet documented all the fish species that are preying on zebra mussels in Lake Champlain.
Because the concentration of calcium in the water of Lake Champlain is very low, the zebra mussels in Lake Champlain have very thin shells. The thin shells of the zebra mussels in Lake Champlain may make them especially vulnerable to predation, and this may explain why we are seeing more predation on zebra mussels in this lake than in other North American locations.
The relationship we found between temperature and fish presence and foraging activity clearly suggest seasonality in the use of the zebra mussel beds. If we can begin to characterize the combination of water temperature, bottom habitat structure, water currents, and other factors that influence fish distribution, this may help us to estimate the overall impacts of fish predation on zebra mussels in Lake Champlain.