Zebra and Quagga Mussel FactsZebra and Quagga mussel factsheet
Zebra and Quagga mussel EDRR plan
Origin / Invasion History
Zebra mussels (Dreissena polymorpha) are native to the Black, Caspian and Azov Seas (Benson et al. 2014a) and were first introduced into the Great Lakes through ship ballast water in 1988 and by 1990 they were established in all the Great Lakes and in 1991 they spread into the Illinois and Hudson rivers.
Quagga mussels (Dreissena rostriformis bugensis) are native to the Dneiper River drainage of Ukraine and the Ponto-Caspian Sea (Benson et al. 2014b). The quagga mussel was first discovered in the Great Lakes in 1989 (Benson et al. 2014b). The first reported occurrence of quagga mussels outside the Great Lakes was in 1995; however their distribution is not as widespread outside the Great Lakes as that of the zebra mussel.
Visit the USGS website for the current distribution of zebra and quagga mussels in North America.
Zebra and quagga are freshwater mussels that mature after 1-2 years, and they are dioecious (separate sexes) with external fertilization. The optimal temperature for spawning is between 18-28°C and a fully mature female mussel is capable of producing up to one million eggs per season (McMahon 1996, Benson et al. 2014a). Eggs are fertilized in the water column and hatch into trocophore larva with no shell which lasts for 6-20 hours after which they become free-swimming veliger larvae after 3-5 days (80-100 µm) (McMahon 1996). This microscopic planktonic larval stage lasts for approximately one month, which can result in long-distance dispersal to downstream areas. They enter the juvenile stage (>400 µm) at around 3-5 weeks which allows the mussel to settle and attach to substrates through byssal threads (McMahon 1996). Before reaching the adult stage, the mussels are most vulnerable to predation, and also require specific temperature, oxygen, substrate and water velocities for successful colonization.
At present, no zebra or quagga mussels have been found in BC waters, and the province does have an ongoing monitoring program (see Lake Monitoring webpage for more information). For further information the Zebra and Quagga mussel factsheet is available for download here.
Distinguishing features of Zebra and Quagga Mussels:
Native Mussels and clams:
In comparison our native mussels are much larger and have a different shape and cannot attach to hard substrate (see pictures below). Additional information on freshwater mussels is available from the BC Species and Ecosystems Explorer and the Freshwater Mussels of the Pacific Northwest (2nd Edition).
Examples of native mussels:
Zebra and Quagga Mussels (top) vs. Native Mussels (bottom):
Zebra and quagga mussels have been introduced by trans-continental shipping from
the Baltic Sea to the Great Lakes. From there, they have spread throughout North
America by attaching to watercraft hauled between waterbodies (Benson et al. 2014a,b).
These species can be moved between watersheds while attached as juvenile or adult
mussels to watercraft that are transported between waterbodies. Zebra and quagga
mussels can survive for extended periods of time out of the water and can be easily
overlooked in the smaller juvenile stages when attached to a boat.
Provinces and States listed as contaminated under Schedule 5 of the Controlled Alien Species Regulation (October 2014).
Why Do We Care?