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Proceedings 2009/045

Proceedings of the National Peer Review of the Risk Assessments of two solitary and three colonial Invasive Tunicates in both Atlantic and Pacific Canadian Waters; March 13-14, 2007

Chairperson: N.E. Mandrak
Editors: Erika Reese and Dave Marson


A draft risk assessment was developed to evaluate the biological risk associated with the following tunicate species: Botryllus schlosseri, Botrylloides violaceus, Ciona intestinalis, Didemnum spp., and Styela clava for both the West and East coasts of Canada. The purpose of this meeting was to peer review the draft following the Canadian Science Advisory Secretariat (CSAS) peer review process. The meeting was held on March 13-15, 2007, in Charlottetown, Prince Edward Island. There were a total of 37 participants including the CEARA Directorate, the Tunicate Risk Assessment team leader and individuals (from within and outside DFO Science) with relevant expertise in tunicates or marine invasive species.

The peer review process resulted in the changes to several of the risk assessment rankings. It was suggested that additional research regarding parasites, pathogens and fellow travelers is needed in order to reduce the uncertainty of their threat. The basic biology of the tunicate species related to areas of high uncertainty must also be addressed through additional research to fill information gaps. Another recommendation suggested the need for a central registry that would provide a place for the living document to be housed where managers could access the information while updates and refinements continue.

It was felt by some members that the predictions for the East Coast waters were not as accurate as they could be, and it was suggested that through the division of the East Coast into DFO’s eco-regions the assessment could be more accurate.

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