Mussel growth
The zebra and quagga mussels were observed to be actively
filtering throughout the experiment. Only one zebra
mussel and no quagga mussels died during the 21 days. In
all but one of the cores with live zebra or quagga mussels,
there was a net increase in mass and average length of the
mussels. Mass increase in these cores ranged from 5% to 30% and length increased by 2%–12%. Both mass (df = 7,
F = 92.7, p < 0.0001) and length (df = 8, F = 54.7, p =
0.0001) increase varied significantly by treatment. Quagga
mussels showed a significantly greater increase in length
and mass than zebra mussels, but there was no significant
difference in growth between zebra mussels on the sediments
and those suspended in the water column (Tukey’s
test, p < 0.05).