For aerial applications , do not apply this pesticide within 100 yards from the edge of water within the areas described above. For aerial applications , do not apply this pesticide within 200 yards from the edge of water within the areas described above. 20 Do not apply directly to water within the shaded area. The penitent mussel is a bivalve mollusk about 2.1 inches long. It has a yellowish, rhomboid shell with irregular growth lines and a radically sculpted posterior.
Females have large, grooved swellings projecting behind the shell.
In the parasitic larval stage of the mollusk lifecycle, it is dependant on fish within its habitat for nutrients and mobility. However, only a few host fish are known. Mature mussels bury themselves in the riffles and shoals and feed by siphoning phytoplankton and other plant matter from the water. Reverse siphoning is used to expell undigestible particles from the shell. Silt in the water can kill mussels by clogging these feeding siphons.