Since the 1960s, mussels have been harvested for export to Japan, where the shells are cut up and ground into round pellets and implanted into oysters to produce cultured pearls.
Mussels are no longer abundant.
Of the eighty species native to Illinois, more than half are threatened, endangered, extirpated, or extinct. The Mississippi - Lower Rock River RRA includes major rivers, bottomlands, upland forests, prairies, and river bluffs. This RRA has a relatively high total acreage of Natural Areas due primarily to Mississippi River sites. Bald eagles once commonly nested along the large rivers in Illinois. Declines in the continental population were reflected in the small number of eagles observed in Illinois from the late 1800s to the mid 1900s.