in canadian waters and pdf... · risk assessment for new zealand mudsnail (potamopyrgus...

Risk Assessment for New Zealand

Mudsnail (Potamopyrgus antipodarum)

in Canadian Waters

Thomas W. Therriault1, Andrea M. Weise2,

Graham E. Gillespie1, and Todd J. Morris3

Department of Fisheries & Oceans Canada

1) Pacific Biological Station, Nanaimo, BC

2) Institut Maurice-Lamontagne, Mont Joli, QC

3) Canadian Centre for Inland Waters, Burlington, ON

• New Zealand mudsnail (NZMS) was identified as species of concern by CEARA based on global invasion history.

• With reports from the Great Lakes and Pacific Coast, a formal risk assessment was deemed necessary to characterize the potential risk posed to Canadian waters by this species.

Introduction

• CEARA adopted DRAFT guidelines for conducting biological risk assessments in 2006. These guidelines were revised in 2008 but have not been finalized.

• The initial guidelines were developed based on the Canadian National Code on Introductions and Transfers of Aquatic Organisms while the most recent version follows a general invasion cycle.

General RA Framework

• Step 1: Determining the Probability of a Widespread Invasion.

• Step 2: Determining the Consequences (Impacts) of a Widespread Invasion.

• Step 3: Combining the Probability of a Widespread Invasion with the Consequences (Impacts) of a Widespread Invasion (Determining Risk)

General RA Framework

RAs for NIS

Survive

Arrive

Spread

Reproduce

Consequences

• Risk = Probability X Impact (Consequence)P1

P4

P3

P2

I1 I2 I3I4

Stages of InvasionEvent Probability

(P)

Impact (I) Impact Description

Arrive P1 I1 Species arrives but does

not survive

Survive P2 I2 Species survives but

does not establish

Establish P3 I3 A local population is

established

Spread P4 I4 Widespread invasion

Stages of InvasionOutcome Probability Impact Risk

Arrives (A), but no

survival

PA = Min(P1, 1 – P2) IA = I1 RA = (PA,IA)

Survives (S), but

no reproduction

PS = Min(P1,P2, 1 – P3) IS = I2 RS = (PS,IS)

Establishes (E)

locally, not

widespread

PE = Min(P1,P2, P3,1 – P4) IE = I3 RE = (PE,IE)

Widespread (W)

invasion

PW = Min(P1,P2, P3, P4) IW = I4 RW = (PW,IW)

Overall risk RTotal = Max(RA,RS,RE,RW)

The Risk Matrix

Impact /

Consequence

Very High

High

Moderate

Low

Very Low

Positive

Very Low Low Moderate High Very High

Probability of Invasion

• Temporal: 5 years

• Spatial

1. Laurentian Great Lakes/St. Lawrence estuary;

2. Pacific Freshwater;

3. Arctic Freshwater;

4. Gulf of Mexico Freshwater;

5. Hudson Bay Freshwater;

6. Atlantic Freshwater;

7. Pacific Coastal; and

8. Atlantic Coastal

Scope and Scale

Canadian Freshwater Drainages

• Risk was assessed for each unit based on:

– Literature (primary and gray)

– Environmental Niche Modeling (GARP)

– Expert Survey

• Vectors/Pathways

• Impacts

– Input from CSAS Review Meeting

Additional Information

Biological Review and Current

Distribution of

New Zealand Mudsnail

Predicting the Potential

Distribution of New Zealand

Mudsnail in Canada

GARP Model

• Genetic Algorithm for Rule-set Prediction

• Used geo-referenced environmental data

– 0.5 degree grid

– Terrestrial and climate surrogates for freshwater data

• NZMS current North American distribution

– 0.5 degree grid

– Reduces presence records from 1,865 to 224

Environmental Data

• Elevation (m)

• Flow accumulation (km2)

• Ground frost frequency

(d)

• Maximum annual

temperature (1961-1990,

C)

• Mean annual temperature

(1961-1990, C)

• Minimum annual

temperature (1961-1990,

C)

• Precipitation (mm)

• Slope (m)

• Solar radiation (W/m2)

• Topographic index

• Wet-day frequency (d)

• Surficial geology

Potential Canadian Distribution

Eastern Detail

Western Detail

Variable Hierarchical partitioning (%)

Maximum annual air temperature 48.1

Mean annual air temperature 23.4

Minimum annual air temperature 13.8

Radiation 8.5

Flow accumulation 2.9

Topographic index 2.5

Slope 0.6

Precipitation 0.1

Wet day index 0.1

Partitioning of Variables

Using an Expert Survey to

Inform the Risk Assessment of

New Zealand Mud Snail in

Canada

• Survey primarily targeted individuals familiar with NZMS but also sent to experts on invasive species/gastropods

• Of 125 individuals targeted, 70 responded

• Identified the relative importance of 2 primary and 30 secondary invasion vectors

• Identified impacts to 8 ecological endpoints

• Uncertainty also characterized

Expert Survey Overview

Vector ImportanceVector Importance

Vector of Introduction / Spread

Very High

High Moderate Low Very Low

N

Primary Vector

Commercial movement of contaminated aquaculture products (live fish and eggs)

13(3)

12(4)

10(14)

5(14)

1(6)

41(41)

Ballast water – foreign port

7(6)

16(4)

5(13)

8(13)

5(6)

41(42)

Vector Importance


Very High


N

Secondary Vectors

Attachment to gear (i.e. waders, boots, etc.) (RA)

17(1)

17(3)

6(6)

1(16)

0(11)

41(37)

Indirect attachment as fouling through mud, macrophytes and algae (RWU)

15(2)

15(3)

9(11)

2(14)

0(8)

41(38)

Rheotactic movement (ND)

13(2)

7(4)

9(12)

7(9)

1(7)

37(34)

Natural drift (ND) 10(3)

8(5)

8(14)

10(8)

2(5)

38(35)

Vector Importance

Vector types: Natural Dispersal (ND), Transport by Secondary Organisms (TSO),

Natural Resources Activities (NRA), Fish Hatcheries (FH), Recreational Anglers

(RA) and Recreational Water Users (RWU).

Vector Importance


Very High


N

Contaminated hatchery transplants - live passage through fish digestive systems (FH)

6(3)

16(5)

11(10)

4(10)

1(6)

38(34)

Contamination of water supplies (FH)

5(1)

16(6)

14(10)

3(12)

0(5)

38(34)

Professional field research gear and clothing (NRA)

8(1)

15(3)

9(12)

4(12)

2(7)

38(35)

Waterway operations removing or transporting substrate material (i.e. dredging) (NRA)

4(4)

15(8)

12(11)

6(8)

1(3)

38(34)

Attachment to floating aquatic macrophytes and algae (TSO)

8(3)

14(3)

9(17)

7(10)

1(5)

39(38)

Fish Stocking (FH) 8(1)

14(6)

10(13)

4(11)

1(4)

37(35)

Vector Importance

Vector Importance


Very High


N

Flood events causing dislodgement - natural or human caused (ND)

5(3)

14(6)

10(13)

8(9)

1(4)

38(35)

Within bird and fish gastrointestinal tracts (TSO)

3(4)

14(5)

12(13)

9(12)

2(3)

40(37)

Inadvertently distributed in live bait or when bait containers are discarded (RA)

3(3)

13(7)

9(16)

13(8)

0(0)

38(34)

Embedded in mud on anchors and other watercraft accessories (RWU)

10(3)

12(4)

10(12)

6(11)

0(5)

38(35)

Entrained in water lines or livewell/bilge of watercraft's (RWU)

3(2)

12(8)

10(11)

11(10)

1(3)

37(34)

Attachment to aquatic ornamental plants -wholesale/retail (TSO)

7(2)

11(7)

10(12)

10(10)

0(4)

38(35)

Vector Importance

Vector Importance


Very High


N

Freshwater tanks 3(6)

7(6)

16(10)

9(7)

1(4)

36(33)

Citizen and classroom monitoring groups (NRA)

6(2)

9(4)

15(15)

7(10)

1(4)

38(35)

Canal and ditch maintenance (NRA)

3(5)

11(7)

15(13)

7(6)

1(3)

37(34)

Passive transport by feet or fur of domestic livestock (TSO)

0(6)

5(9)

15(10)

13(8)

4(1)

37(34)

Firefighting machinery or equipment used to fight backcountry forest fires (NRA)

3(7)

5(10)

14(6)

13(9)

3(3)

38(35)

Direct attachment as fouling to watercraft/trailers (RWU)

6(3)

10(6)

13(14)

10(9)

1(4)

40(36)

Vector Importance

Vector Importance


Very High


N

Hikers, Backpackers, Horseback riders, Bicyclists (RWU)

0(4)

4(8)

14(14)

19(8)

2(1)

39(35)

Deliberate release 3(9)

2(5)

5(7)

16(10)

12(5)

38(36)

Movement of live/dead fish between watersheds (RA)

2(4)

9(7)

12(15)

16(8)

0(2)

39(36)

Volitional movement (ND)

4(3)

8(6)

7(6)

16(13)

1(5)

36(33)

Within bird bills, feathers or on legs (TSO)

2(6)

6(6)

13(12)

15(9)

1(2)

37(35)

Passive transport by semi-aquatic and terrestrial wildlife (TSO)

0(5)

8(10)

13(16)

15(3)

3(2)

39(36)

Vector Importance

Vector Importance


Very High


N

Free-Floating juveniles on water surface (ND)

8(5)

6(5)

9(12)

13(9)

1(3)

37(34)

Ballast discharge -coastal shipping

3(4)

8(3)

9(13)

10(8)

7(7)

37(35)

Vector Importance

ImpactsImpact Level

Negative Positive

Ecological Endpoint Very High High Moderate Low Very Low N

Freshwater Biodiversity 6 14 12 5 3 1 41

Protected Areas /

Conservation Areas7 12 6 5 2 1 33

Aquaculture 6 5 8 5 6 1 31

Recreational Fisheries 4 7 12 6 7 0 36

Habitat 7 6 5 10 6 1 35

Estuarine Biodiversity 0 7 7 9 8 1 32

Marine Biodiversity 0 0 1 4 25 0 30

Commercial Fisheries 1 2 10 6 14 0 33

Step 1: Determining the

Probability of a Widespread

Invasion

Region P1 P2 P3 P4

Great Lakes / St Lawrence Very High

(Very Low)

Very High

(Very Low)

Very High

(Very Low)Very High

(Low)

Pacific Freshwater Very High

(Low)

Very High

(Low)

Very High

(Low)

Low

(Moderate)

Arctic Freshwater Low

(Very High)

Very Low

(Moderate)

Very Low

(Moderate)

Very Low

(Low)

Gulf of Mexico Freshwater High

(High)

Very High

(Low)

Very High

(Low)High(Low)

Hudson Bay Freshwater High

(Low)

Very High

(Low)

Very High

(Low)

Moderate

(Moderate)

Atlantic Freshwater Very High

(Very Low)

Very High

(Low)

Very High

(Low)

Moderate

(Moderate)

Pacific Coastal Very High

(Very Low)

Very High

(Very Low)

Very High

(Very Low)

Low

(High)

Atlantic Coastal Low

(Very High)

Very High

(Low)

Very High

(Low)

Low

(Very High)

Ranks (Uncertainty)

Region

PA - arrival

without

survival

PS - survival

without

establishment

PE

establishment

without spread

PW

widespread

invasion

Great Lakes / St Lawrence Very Low Very Low Very Low Very High

Pacific Freshwater Very Low Very Low High Low

Arctic Freshwater Low Very Low Very Low Very Low

Gulf of Mexico Freshwater Very Low Very Low Low High

Hudson Bay Freshwater Very Low Very Low Moderate Moderate

Atlantic Freshwater Very Low Very Low Moderate Moderate

Pacific Coastal Very Low Very Low High Low

Atlantic Coastal Very Low Very Low Low Low

Overall Probabilities


Consequences (Impacts) of a

Widespread Invasion

Region Biodiversity Habitat Aquaculture Commercial

Fisheries

Recreational

Fisheries

Great Lakes / St Lawrence Low

(High)

Low

(High)

Very Low

(Moderate)

Low

(High)

Low

(High)

Pacific Freshwater Moderate

(Very High)

Low

(High)

Very Low

(High)

Very Low

(High)

Low

(High)

Arctic Freshwater Moderate

(Very High)

Low

(High)

Very Low

(High)

Very Low

(High)

Very Low

(High)

Gulf of Mexico Freshwater Moderate

(Very High)

Low

(High)

Very Low

(High)

N/A Low

(High)

Hudson Bay Freshwater Moderate

(Very High)

Low

(High)

Very Low

(High)

Low

(High)

Low

(High)

Atlantic Freshwater Moderate

(Very High)

Low

(High)

Very Low

(High)

Very Low

(High)

Low

(High)

Pacific Coastal Very Low

(High)

Very Low

(High)

Very Low

(High)

Very Low

(High)

Very Low

(High)

Atlantic Coastal Very Low

(High)

Very Low

(High)

Very Low

(High)

Very Low

(High)

Very Low

(High)

Rank of Potential Impacts


Overall Risk of a Widespread

Invasion

The Risk Matrix

Impact /

Consequence

Very High

High

Moderate

Low

Very Low

Positive

Very Low Low Moderate High Very High

Probability of Invasion

Region Biodiversity Habitat Aquaculture Commercial

Fisheries

Recreational

Fisheries

Great Lakes / St Lawrence Low

(High)

Low

(High)

Low

(Moderate)

Low

(High)

Low

(High)

Pacific Freshwater Low

(Very High)

Low

(High)

Low

(High)

Low

(High)

Low

(High)

Arctic Freshwater Low

(Very High)

Low

(High)

Low

(High)

Low

(High)

Low

(High)

Gulf of Mexico Freshwater Moderate

(Very High)

Low

(Very High)

Low

(High)N/A

Low

(High)

Hudson Bay Freshwater Moderate

(Very High)

Low

(High)

Low

(High)

Low

(High)

Low

(High)

Atlantic Freshwater Moderate

(Very High)

Low

(High)

Low

(High)

Low

(High)

Low

(High)

Pacific Coastal Low

(High)

Low

(High)

Low

(High)

Low

(High)

Low

(High)

Atlantic Coastal Low

(Very High)

Low

(Very High)

Low

(Very High)

Low

(Very High)

Low

(Very High)

Overall Risk Assessment

Conclusions

Conclusions

• Overall risk of NZMS to Canadian ecosystems was designated low to moderate

– Moderate risk to Freshwater Biodiversity in Gulf of Mexico, Hudson Bay and Atlantic drainages

– Low for all other ecological/geographical combinations

• Risk at smaller scales could be significantly higher

Conclusions

• Vectors have high levels of uncertainty

– More work needed to decrease uncertainty

• Difficult to predict impacts on Canadian

ecosystems

– More work needed to understand NZMS biology and

ecology

• Current distribution uncertain

– Education and outreach for better monitoring of NZMS

distribution in Canada

Conclusions

• Niche modeling can be improved

– Need to update as new occurrences are reported

– Need to explore other environmental layers

– Modeling at smaller scales may be appropriate

for management advice

Conclusions

• This assessment represents a starting point

– This biological assessment can inform overall

assessments that incorporate socio-economic

considerations, risk management and risk

communication

– Should be revisited as new data become

available and information gaps are filled

Documents

• Available at the Canadian Science Advisory

Secretariat website

– http://www.isdm-gdsi.gc.ca/csas-

sccs/applications/publications/index-eng.asp

– CSAS Proceedings Series 2010/023

– CSAS Research Document 2010/108

– CSAS Science Advisory Report 2010/065

Thank you!