Do Freshwater Mussels Contain Pearls? Understanding the Relationship Between Freshwater Mussels and Pearls in One Article

Freshwater mussels are a general term for a group of animals in the family Unionidae, phylum Mollusca. In some places they are called mussel shells, waier, and other names. They live on the bottom of freshwater lakes, ponds, rivers, and other waters, semi-buried in mud and sand. Their meat is edible and can also be used as bait for fish and poultry and as feed for poultry and livestock. In some areas they are used for freshwater pearl cultivation. Let us take a look below at whether freshwater mussels contain pearls!

Do Freshwater Mussels Contain Pearls?

Freshwater mussels can contain pearls, but not every freshwater mussel has one, and generally wild freshwater mussels do not easily grow pearls. The formation of a pearl requires a small foreign insect or small particle of sand or stone to enter the mussel's body. Over a long period, in order to avoid irritation, the mussel secretes nacre to wrap the small insect or small grain of sand, and only after many years can a pearl form. Natural pearls are generally of the finest quality, while artificially cultivated pearls are relatively cheap.

How Are Pearls Formed?

1. External cause: The mantle of the mussel is stimulated by the intrusion of a foreign object (sand grain, parasite). The epidermal cells at the stimulated site use the foreign object as a nucleus, and the pearl sac cells secrete nacre, coating the nucleus layer upon layer to form a pearl. This kind of pearl is called a “nucleated pearl”.

2. Internal cause: After the outer epidermis of the mussel's mantle receives pathological stimulation, some cells undergo cell division and then separate, wrapping themselves in the organic matter they secrete, while gradually sinking into the connective tissue of the mantle. After forming a pearl sac, a pearl is formed, called a “non-nucleated pearl”.

What Kinds of Freshwater Mussels Are There?

1. Cristaria plicata: Cristaria plicata is also called the cockscomb mussel, lake mussel, soft mussel, and other names. It is a freshwater benthic bivalve in the genus Cristaria, family Unionidae, and is common along the coast of China. It generally inhabits the mud bottom or muddy sand bottom of lakes, rivers, ditches, and ponds in freshwater, slow-flowing, and still waters.

2. Hyriopsis cumingii: Hyriopsis cumingii is also called the freshwater mussel, pearl mussel, freshwater pearl mussel, triangle mussel, and other names. It is widely distributed in Hunan, Hubei, Anhui, Jiangsu, Zhejiang, Jiangxi, and other provinces, with especially dense distribution in China's Dongting Lake and medium-sized lakes.

3. Anodonta woodiana: Anodonta woodiana is also called the vegetable mussel, freshwater mussel, round mussel, and other names. It is distributed in rivers and lakes throughout China. Its meat is edible and is also suitable as bait for fish and poultry and as feed for poultry and livestock. In some areas it is used as a freshwater pearl mussel.

4. Lamprotula leai: Lamprotula leai is also called the hemp-skin mussel, hemp waiwai, and other names. It is distributed in Hebei, Anhui, Jiangsu, Zhejiang, Jiangxi, Hubei, Hunan, Guangdong, Guangxi, and other places, with especially high yields in large and medium-sized lakes and rivers in the middle and lower reaches of the Yangtze River.

5. Nodularia douglasiae: Nodularia douglasiae has a medium-sized shell. The shell is relatively thin but hard, and its shape is oblong-elliptical. Its length is more than 2 times its height. The two sides of the shell are asymmetrical. The front part of the shell is short and round, while the rear part is not elongated and the end is slightly narrow and flattened. The shell surface is dark brown or black.