The water the mussels filter through their bodies has become dangerous to them. “A lot of our streams are not as clear as they once were,” Mair says. “With all of the factories and discharges and agriculture and increases in human population, there’s a lot of pressure on our freshwater mussels.” They arent able to thrive in these new conditions. When mussels eat they clean the water by removing phytoplankton, bacteria, other undesirable particles and chemicals. Which helps clean our water.