Because there were no controls on this industry, mussels were over-harvested and the number of many species dwindled. This, along with the use of plastic replacements, put an end to the pearl button industry. In the 1960's, the Japanese cultured pearl industry began to expand. If tiny pieces of sand or mussel shell are inserted into oysters they surround the disturbance with a silicate, creating a pearl. The demand and high prices from this industry has resulted in increasing the occurrences of illegal mussel harvesting.
Mussels play an important role in the aquatic ecosystem.
Many different kinds of wildlife eat mussels, including raccoon, otters, herons, and egrets. Mussels filter water for food and thus are a purification system. They are usually present in groups called beds. Although their lives appear boring, their reproductive strategies are quite fascinating. After the male has dispersed sperm that is carried by currents to the female where fertilization occurs, the fertilized eggs are transformed into a larval state inside the female.