Dreissena polymorphaThis freshwater mussel is an excellent water filter-feeding organism. Originally native to Eurasia, it has been accidentally introduced into European and North American waters where it poses a threat to local ecosystems.
1.They originated from the Caspian Sea and the Black sea region.
In the 19th century, it was introduced to Europe made its way to North America in the 1980s.
2.Zebra mussels live in water, attached to rocks, sunken logs, wrecks and manmade infrastructure.
It is a species that readily adapts to a variety of environmental and trophic conditions.
3.Their mussel is triangle-shaped, beige with dark brown stripes.
In some populations, albino forms occur, sometimes in great numbers.
4.Although it is a freshwater species, it can live in salty environments.
Zebra mussels tolerate salinity up to 6 ppm. When removed from the water, they can survive for about a week.
5.They are medium size clams, which adult forms can grow up to 5,1 cm.
Average specimen dimensions are between 25 to 40 mm in length, 13 to 18 mm in height and 17 to 23 mm in width.
6.They feed on detritus.
To acquire food zebra opens its shell. An individual is capable of filtering about one liter of water daily.
7.They reproduce sexually.
Fertilization takes place in water. The number of eggs produced by a female may reach one million. Usually, in every cycle, from 30 to 40 thousand eggs can be produced.
8.Zebra mussel larvae are called veligers.
After hatching, they are suspended in water for a few weeks (10 to 24 days, depending on conditions) and settle down on a suitable surface afterward. It is estimated that about 90% of larvae do not survive the settling down process.
9.They are excellent water filterers.
Thanks to their filtering efficiency, they clean water making it more transparent and allowing algae to grow on greater depths. This process captures edible seston particles and rejects inedible particles, formed as in so-called pseudo-fecal matter. This contributes to clearing the water of suspended solids and reducing symptoms of eutrophication. A significant amount of fecal matter and pseudo-fecal matter falls to the bottom of the body of water where creates a trophically very rich environment. It is partially used as food by other benthic organisms.
10.They fall prey to fish and waterfowl.
While birds eat adult forms, some fish species feed on larvae too. Among mammals, muskrats are one of their common predators.