Texas Mussel Watch

The Decline of the Texas Mussel

Reasons for decline in freshwater mussel populations:

Freshwater mussel

• Changes in flow rates of rivers and streams due to droughts, floods, or building of dams;
• Increased deposition of soft silt due to excessive run-off;
• Scouring of stream beds during storm events;
• Increased amounts of aquatic vegetation;
• Lack of suitable native fish hosts for larval stage;
• Aquatic contaminants; and,
• Introduction of exotic species.

Adult mussels can range from less than one inch in length to nearly 12 inches long. Some species have thin shells and a life-span of only 5 or 6 years, while others have thick shells and can live well over 50 years.

Shells vary both on the inside and outside of mussels, depending upon the mussel species. Color, texture, and shape variations in shells are used to help identify different types of mussels.

Tampico Pearlymussel

Freshwater mussels have been collected by commercial musselers for the cultured pearl industry. A cultured pearl is formed by taking a round core from the shell of some of our larger species of freshwater mussels and inserting that core into a clam. Freshwater pearls have also been collected by musselers. One species, the Tampico pearlymussel is known to produce the rare Concho River Pearl.

Losing our freshwater mussels would mean …
the loss of an important indicator of the health of aquatic ecosystems.

Mussels are often the first species to vanish when environmental conditions change or decline. As filter feeders, mussels concentrate substances that are dissolved in the water. Mussel tissues can be examined to check for many toxic chemical pollutants of our rivers, lakes, and streams. Healthy mussel populations mean purer water for humans and countless aquatic plants and animals.