The zebra mussel belongs to the representatives of the autolamellibranchiata, a subclass of the class of mussels (bivalvia). This freshwater mussel goes through a rare free-swimming larval stage.
They are triangular in shape, and they are only about 1 ½ inches in size. This is roughly the size of a fingernail. They got their name because of the eye-catching bowl. It is yellowish to light brown in color and has dark brown to black, mostly jagged or wavy stripes.
The mussel feeds on plankton and detritus, which it filters out of the water. It can reach an age of up to 10 years. After a year, it is sexually mature and can produce up to 1 million eggs a year.
The zebra mussel was originally native to freshwater waters in the Eurasian region. The earliest documented evidence in Europe comes from the Miocene (5.3–23 million years ago). Their population steadily decreased until the 18th century. The increasing shipping traffic from the Black Sea across the Danube resulted in a re-immigration. The mussels attach themselves to ship hulls or come as larvae via the ballast water of ships into new habitats, where they encounter few or no predators. This is why one speaks of an invasive mussel species, i.e., a non-native species spread in their new area. Worldwide shipping traffic has led to a massive increase in zebra mussels in the great lakes of North America and in the major rivers since the 1980s. They have also been found in Texas, Colorado, Utah, Nevada, and California.