Quagga mussel

Dreissena bugensis


Habitat: estuarine habitats, lakes, water courses


Description: Dreissena bugensis commonly has alternating light and dark brown stripes, but can also be solid light brown or dark brown. It has two smooth shells that are shaped like the letter “D”. These mussels are usually less than 2 inches in length. In new populations, most mussels are young and therefore very small (under ¼ -inch long). Zebra mussel and the quagga mussel are very similar in their appearance. They can sometimes be differentiated by the shape of the shells. However, expert knowledge is needed to distinguish these two species.


Origin and Distribution: Ponto-Caspian region (Black, Caspian, Azov Seas). Currently invasive in North America where significant and costly efforts are in place to reduce spread and impact. Also spreading within continental Europe


Impacts: Like the zebra mussel, the quagga mussel increases water clarity and decreases phytoplankton abundance. Quagga mussels also cause a reduction in zooplankton populations. Native species of Unionids can suffer as a result of the introduction of both zebra and quagga mussel.
This species is also an economic pest acting as a fouling organism and increasing the cost of water treatment and the cost to industries dependent on freshwater e.g. hydroelectric power stations.


How might it get here? Fouling of boats and other machinery. Ballast water.


Prevent Spread:


  • Do not introduce quagga mussels to the island of Ireland
  • Prevent fouling of boats and equipment
  • Clean all equipment including boats before moving to new waterbodies



Invasive Species Ireland

Invasive Species Ireland