DEVELOPMENT OF A FRAMEWORK FOR MANAGEMENT OF AQUATIC INVASIVE SPECIES OF CONCERN FOR YUKON: LITERATURE REVIEW, RISK ASSESSMENT AND RECOMMENDATIONS Prepared by: Maria Leung and Al von Finster Prepared for: Fish and Wildlife Branch, Environment Yukon April 2016 DEVELOPMENT OF A FRAMEWORK FOR MANAGEMENT OF AQUATIC INVASIVE SPECIES OF CONCERN FOR YUKON: LITERATURE REVIEW, RISK ASSESSMENT AND RECOMMENDATIONS Yukon Department of Environment Fish and Wildlife Branch MRC-14-01 Maria Leung and Al von Finster prepared the report under contract to Environment Yukon. This report and its conclusions are not necessarily the opinion of Environment Yukon and this work does not constitute any commitment of Government of Yukon. © 2016 Yukon Department of Environment Copies available from: Yukon Department of Environment Fish and Wildlife Branch, V-5A Box 2703, Whitehorse, Yukon Y1A 2C6 Phone (867) 667-5721, Fax (867) 393-6263 Email: [email protected] Also available online at www.env.gov.yk.ca Suggested citation: LEUNG M. AND A. VON FINSTER. 2016. Development of a framework for management of aquatic invasive species of concern for Yukon: Literature review, risk assessment and recommendations. Prepared for Environment Yukon. Yukon Fish and Wildlife Branch Report MRC-14-01, Whitehorse, Yukon, Canada. Preface Aquatic Invasive Species (AIS) are non-native aquatic species that have a detrimental impact on environments that they invade. In Canada, millions of dollars are spent each year on control alone. From experiences across the country and around the world, experts have found that strategies aimed at preventing the spread of AIS are preferable to diverting financial resources to programs aimed at managing AIS after they have established. In Yukon, we have the opportunity to prevent the spread of additional AIS and to focus on prevention rather than management. Resources can be directed towards education, prevention, detection, and rapid response. To inform such programs and to tailor them for maximum effectiveness, it is important to understand the characteristics of the aquatic invasive species that pose the largest threat. In 2011, Environment Yukon hired contractors Maria Leung and Al von Finster to investigate those AIS that pose the greatest risk to Yukon’s environment and economy, based on objective criteria. They developed the following report and recommendations for the prevention, detection, and management of 16 AIS. Environment Yukon wishes to make this information widely available. Although this report is not necessarily the opinion of Environment Yukon and does not constitute any commitments by Environment Yukon, work is underway to implement several recommendations. Following the completion of this report, new evidence has suggested that didymo is native to southern Canada. Since it is unclear whether this species is invasive in Yukon, Environment Yukon has begun sampling for didymo, in an effort to learn more about its distribution and to collect genetic samples to learn the origin of this species. Work on didmyo in Yukon is ongoing. Framework for management of aquatic invasive species in Yukon iii page is intentionally blank Framework for management of aquatic invasive species in Yukon iv Table of Contents Preface .................................................................................................... iii Table of Contents ..................................................................................... v List of Tables .......................................................................................... vi Introduction ............................................................................................ 1 Risk Assessment of AIS to Yukon ............................................................. 1 Recommendations for the Prevention, Detection, and Management of AIS in Yukon .................................................................................................. 2 Didymo ........................................................................................................ 4 Zebra mussels ............................................................................................. 6 New Zealand mud snail ................................................................................ 8 Waterweed ................................................................................................... 9 Eurasian watermilfoil ................................................................................. 10 Whirling disease ........................................................................................ 12 Prevention of Introduction ..................................................................... 13 Conclusions and Next Steps ................................................................... 17 APPENDIX 1 Overview of AIS: Likelihood and Consequences of Yukon Invasion ........................................................................... 19 APPENDIX 2 Risk Assessment for Aquatic Invasive Species in Yukon. .. 66 References ............................................................................................. 69 Framework for management of aquatic invasive species in Yukon v List of Tables Table 1. The relative risk of 16 AIS to Yukon, based on relative scores assigned in 26 risk assessment criteria, grouped into 4 categories. .................................................................................... 3 Table 2. Summary of recommended education and public outreach initiatives and best practices guidelines for deterring the introduction of AIS, by identified target audiences. The letters reference the item on the “best practices” list and the numbers reference the item on the “public outreach and education” list. ... 14 Framework for management of aquatic invasive species in Yukon vi Risk Assessment of AIS to Introduction Yukon The increasing presence of Aquatic To determine the AIS of greatest Invasive Species (AIS) in Canada is concern in Yukon, a ranking scheme causing the displacement of native was developed by modifying relevant flora and fauna, damaging criteria from other invasive species infrastructure, and costing Canadians assessments (e.g., Alberta Alien millions of dollars annually to control. Species Risk Assessment Tool) and Policies to control AIS (which can be adding other pertinent criteria diverse species of algae, plants, and (Appendix 2). The scheme was kept fish) have largely been reactive rather simple to avoid over-extrapolation of than proactive, and focused on limited data on AIS, both potential species rather than vectors (Strayer and realized, within Yukon; and for 2009). Strategies aimed at preventing clarity about how the score and the spread of AIS are preferable to subsequent ranking were determined diverting financial resources to for each species. The drawback to this programs aimed at managing AIS simplicity is that some subjective after they have established. judgement remains due to lack of In Yukon, the number of known or explicit definitions of relative suspected AIS is small compared to terminology. For example, terms like the rest of Canada. That means the high, moderate, and low were seldom opportunity to prevent the spread of defined by numerical ranges as in additional AIS in Yukon still exists. more detailed and objective Up to now, there has been no plan in assessments (e.g., Jordan et al. place to prevent, detect, monitor, or 2010). To mitigate subjectivity, the 16 manage AIS in Yukon, and there has AIS were assessed simultaneously been no coordinated effort to increase such that subjective assessments public awareness of the implications were made relative to other species. of AIS introduction. The 26 criteria chosen to Knowledge about AIS in northern determine the relative risk of the 16 regions is generally quite minimal. AIS fit into 4 categories: 1) likelihood This report begins to address some of of introduction; 2) likelihood of the unknowns by first reviewing persistence; 3) ecological literature on 16 species that have consequences; and 4) economic and already established, or could social consequences. Only criteria establish, in Yukon (see Appendix 1); that had potential for distinguishing then ranking the relative risks of the 16 AIS were included. those select AIS; and finally, offering Questions within each category recommendations on the prevention were weighted evenly except for 2: and management of 6 AIS that are of question 3 places more emphasis on comparatively highest risk—both pathways in Yukon that are more ecologically and economically—to likely to facilitate spread of AIS; for Yukon. example, boats, fishing, and recreational equipment pose a much Framework for management of aquatic invasive species in Yukon 1 larger risk than the live-fish-food invertebrates travel with cultivated market; and question 10 is given less fish. The criteria in the “economic and weight because organisms capable of social impacts” section were cloning tend to be prolific, but are not particularly difficult to objectify. Some always more prolific than organisms of these also magnified a single issue. that must reproduce sexually. The For example, AIS causing unsightly numeric responses to each question dead fish affects questions 23, 24, or criterion were tallied so that each and 26. category received a score for each species. Recommendations for the At the next step, each of the 4 categories was also given equal weight Prevention, Detection, and by adjusting their scores out of 25. Management of AIS in Yukon