Proceedings 2012/059

Proceedings of the National Risk Assessment of Zebra Mussel, Quagga Mussel and Dark Falsemussel; March 27-28, 2012

Chairperson: Marten Koops
Editor: Sherry Walker

Summary

In freshwater and some estuarine ecosystems, the Zebra Mussel (Dreissena polymorpha) and Quagga Mussel (D. rostriformis bugenis), both native to the Ponto-Caspian Region of Eastern Europe, have a long history of invasion in aquatic ecosystems in both Europe and North America.  These two species were introduced to the Great Lakes in the mid-1980s as a result of ballast water discharge from ships.  These mussels have rapidly dispersed throughout the Great Lakes region into river systems and smaller lakes. As well, a closely related dreissenid mussel species, the Dark Falsemussel (Mytilopsis leucophaeta), was identified on a boat being trailered across western Canada, raising concerns that this species could also pose a risk to Canadian freshwater ecosystems and was also evaluated in this risk assessment. Dreissenid Mussels have had significant environmental and socio-economic impacts due to their ability for rapid dispersal, resulting in severe negative impacts on food webs and nutrient processing. As a result of the significant impacts associated with these mussels as well as a steady movement west, several western provinces requested Fisheries and Oceans (DFO) (through Canada’s Centre of Expertise in Risk Assessment, CEARA) to conduct a risk assessment for Zebra, Quagga and Dark FalseMussels. This risk assessment considered probabilities of survival (habitat suitability) and arrival to 108 Canadian sub-drainages and the ecological impacts associated with these species. The ecological risk posed by these species was determined using an established Risk Matrix. This risk assessment was peer reviewed as the key scientific working paper in a CSAS National Peer Review Process held on March 27 and 28, 2012 at the DFO Freshwater Institute in Winnipeg, Manitoba. The results are presented in the science advisory report and research document for this CSAS national peer review process.

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