Risk Assessment of Ship-Mediated AIS Introductions to the Pacific Region of Canada. Sarah Bailey

Transcription

1 Risk Assessment of Ship-Mediated AIS Introductions to the Pacific Region of Canada Sarah Bailey 1

2 Background Transport Canada regulates shipping activity Fisheries and Oceans Canada leads science on aquatic invasive species (AIS) to guide policy and regulations Formal Science Advice request to conduct risk assessment of shipping activities in Canada 4 regional RAs, feeding into a national RA 2

3 RISK ASSESSMENT 101 Centre of Expertise for Aquatic Risk Assessment Fisheries and Oceans Canada Burlington, Ontario 3

4 Initiation RISK ANALYSIS = assessment + management + communication Identify hazards Estimate the likelihood of occurrence RISK ASSESSMENT RISK MANAGEMENT Develop recommendations and describe uncertainty Estimate the magnitude of the consequences Evaluate mitigation options for efficacy, feasibility, impacts Develop conclusions and describe uncertainty Identify mitigation options advice Decision RISK MANAGEMENT Communication of decision RISK COMMUNICATION 4

5 Why Use a Risk Approach? Risk = likelihood, and severity, of an undesirable event Uses a probability to describe the chance that an event will occur, when the outcome of the event is unknown (i.e., many risks not deterministic) RAs incorporate (un)certainty of risk estimate: Scientific (e.g., statistical, modeling, physical variability) Human-based (bias, human error) 5

6 Biological Risk Assessment for AIS Likelihood of an AIS introduction probabilities of arrival, survival, establishment, and spread Magnitude of consequences (ecological impacts) Uncertainty considers quality and quantity of data available to rank likelihood and magnitude provides risk managers with indication of the inherent strengths and weaknesses in the risk assessment 6

7 How are Risk Assessments Useful? Prioritize future research needs Direct monitoring, early detection and rapid response activities Identify risky species and pathways for regulation Development and implementation of prohibition lists Analyze effectiveness of regulations did they decrease risk? Identification of secondary pathways to prevent spread 7

8 Main Objective Provide advice about the level of risk of ship-mediated invasions to different areas of Canada Identify gaps in current regulatory program 8

9 The Approach Risk Assessment (RA) = P(Introduction) x Impact Where P(Introduction) = P(Arrival) x P(Survival) In line with previous work of CEARA e.g., Herborg & Therriault (2007) Didemnum sp. 9

10 Species RA vs. Pathway RA Species RA driven by biology: measure propagule pressure by vector(s) / pathway(s) niche models used to predict new range based on native range Impact predicted from biological studies and/or past history Pathway RA driven by vector analysis: multiple species involved identity/native range/impacts may be unknown 10

11

12 Ship Category International transoceanic vessels International coastal U.S. vessels Internationalexempt vessels Risk Assessment Step 1A Step 1B Volume of ballast water discharge (Data source: VTOSS, NBIC & TCBWD) Top 3 ports Environmental similarity (Data source: Sylvester and MacIsaac 2010) P (Arrival) P(Survival) Step 1C P(Arrival) X P(Survival) 1 P (Introduction) Step 2 Number of high impact ballast mediated NIS (Data source: Marine Invasives Database) Consequence Step 3 P (Introduction) X Consequence Invasion risk 2 1 Minimum probability approach; 2 Mixed rounding symmetrical approach

13 P(Arrival) - Transit Analysis Methods: Track all vessel transits to, and ballast water discharges at, every Canadian port Assume vessel arrivals and ballast water discharge are proxy measures for propagule pressure Rank values (5 equal categories) Prioritize top 3 ports per region for further assessment 13

14 P(Survival) - Environmental Matching Assesses port similarity, rather than biological tolerances, due to multiple species in pathway Annual average, max., min. water temp & annual average salinity Measure Euclidean distance of environmental parameters between top ports and all connected donor ports 14

15 Impact How to assign impact for multiple, unknown species? Assemble a list of ship-mediated NIS with negative impacts at all connected source ports Assume NIS at multiple ports have multiple opportunities Assign impact ranking (5 equal categories) 15

16 Putting it all Together P(Introduction) = P(Arrival) X P(Survival) [minimum probability approach] Risk = P(Introduction) X Impact [symmetrical matrix approach] P (Introduction) Lower Intermediate Higher Highest Highest Impact Higher Intermediate Lower **Five rank system reduced to three ranks** 16

17 Relative invasion risk to Pacific ports by hull fouling Vancouver Frasery Surrey Prince Rupert Vancouver Fraser Surrey Kitimat International exempt vessels Vancouver Fraser Surrey Crofton P(Introduction) (moderate) International transoceanic vessels Highest International coastal U.S. vessels Magnitude of consequence (moderate) Intermediate Lower Lower Invasion risk (moderate) Intermediate 17

18 Relative invasion risk to Pacific ports by ballast water Vancouver Fraser Surrey Prince Rupert Vancouver Fraser Surrey Port McNeil Vancouver Fraser Surrey Crofton P(Introduction) (moderate) International transoceanic vessel ballast water discharges Highest International coastal U.S. vessel ballast water discharges International exempt vessel ballast water discharges Magnitude of Consequence (moderate) Highest Lower Invasion risk (moderate) Highest 18

19 Important Source ports connected to Vancouver by Ballast Water of Transoceanic Vessels 19

20 Challenges Pathway RAs Survival and Impact measures plausible only at coarse scale No incorporation of current species knowledge Need biological data to calibrate risk levels 20

21 Acknowledgements J. Adams J. Bradie J. Bronnenhuber F. Chan A. Doolittle S. Ellis K. Howland D. Linley J. Martin C. McKenzie J. O Neill T. Sutherland N. Simard C. Wiley B. Cudmore N. Mandrak 21