What’s in YOUR Bucket? Quantifying AIS Introduction Risk from BaitfishMargaret McEachran1*, Nicholas Phelps1

1Minnesota Aquatic Invasive Species Research Center, University of Minnesota*thom4412@umn.edu

ta;

2. Hazard Prioritization: What pathogens should risk managers be mostconcerned about?

Funding for this project was provided by MN DNR Enforcement Division and the Minnesota Aquatic Invasive Species Research Center (MAISRC).

Acknowledgements

1 Boerson, G. et al. Aquatic Invasive Species Hazard Analysis for Aquaculture and Wild Harvest Bait Industry Sectors. (2017). 2 e. g. Gaughan, D. J. Rev Fish Biol. Fisher. 11.2 (2001): 113-123.3 Peeler, E. J., et al. Prev. Vet. Med. 81.1 (2007): 3-20.

Literature Cited

• Minnesota has a valuable aquaculture industry, bait industry, and recreational fisheries that we need to protect.

• Billions of baitfish moved every year for recreational fishing à perceived as a high-risk pathway for the spread of aquatic invasive species (AIS) and disease2.

• Lack of a structured risk assessment framework and great uncertainty for many aquatic hazards limits our ability to understand this risk.

• The purpose of this project is to quantify the actual number of pathogen introductions that occur every year via bait bucket transfer and inform risk-based management decisions.

1. Bait Shop Survey: What hazards are present in the Minnesota live baitfish supply?

• Several non-target species, 10+ macroparasites, and 60+ species of bacteria, some of which are serious pathogens (Table 1) were found in the bait supply.

• Several new viruses of unknown pathogenicity were discovered as a part of this study. Further research is necessary to determine how hazardous they may be to wild fish populations.

• Knowing what AIS and pathogens are present in MN’s bait supply is an important first step in understanding the risks that the bait pathway could present to wild fish populations.

Summary

Figure 1, far left: Golden shiners are a popular bait species in Minnesota averaging 3-4” long.

Figure 2, left:Locations of bait shops sampled as part of Operation Bucket List survey

• We partnered with undercover Conservation Officers from the Minnesota Department of Natural Resources (MNDNR) Enforcement Division to purchase golden shiners (Notemigonus crysoleucas) (fig.1) from bait shops across the state (fig. 2).

• Fish were delivered live the same day to the Minnesota Veterinary Diagnostic Laboratory, where we separated and counted non-target species.

• We used both traditional and novel diagnostic techniques to identify parasites, viruses, and bacteria present in the golden shiners.

4. Risk Assessment: What is the actual risk

of pathogen introduction via bait

bucket transfer?

5. Risk Management: What can be done to

reduce that risk?

1. Bait Shop Survey:What hazards are present in the Minnesota baitfish

supply?

3. Angler Survey: How do angler behaviors contribute to the risk of

disease spread?

2. Hazard Prioritization: What pathogens should risk

managers be most concerned about? maisrc.umn.edu/about-heterosporis

• In the face of an overwhelming number of potential hazards, researchers and managers need a system to prioritize them for further targeted research, management, and prevention.

• We will develop a hazard prioritization matrix to identify 2-4 priority hazards specific to the baitfish pathway in Minnesota.

• Several factors will be considered when evaluating hazards, including:• Likelihood of transfer in bait bucket• Severity of impact if released• Range of susceptible species

• Uncertainty about lesser-researched pathogens is a major issue in aquatic animal health2. Our hazard prioritization matrix will include a certainty factor to take this into consideration when ranking hazards.

• Despite it being illegal, up to 50% of anglers may not properly dispose of their unwanted baitfish, instead dumping them into lakes.

• Understanding patterns of angler behavior surrounding bait use can help us identify targets for education, enforcement, or other management to reduce the number of fish being released.

• We will survey licensed anglers in Minnesota via a mailed survey and an in-person questionnaire administered at boat launches to quantify bait use patterns in the state.

• Using a quantitative approach known as sensitivity analysis ,we‘ll determine which steps in the pathway contribute most to overall risk and identify potential targets for increased management efforts.

• By quantifying the actual, not just perceived risks, we will help to facilitate discussions among agency, industry, and public stakeholders,and inform risk-based management decisions that support the state’s bait and fishing industries while protecting natural resources

World Fishing Network

Table 1: Pathogens of concern found in golden shiners purchased from MN bait shopsPathogen Category # positive Potential impacts on

native speciesOvipleistophoraovariae

parasite 29/52 Ovarian tissue degradation and sterilization

Aeromonassalmonicida

bacteria 3/52 Tissue necrosis,hemorrhages, and death

Vibrioanguillarum

bacteria 3/52 Septicemia, hemorrhages, and death

Yersiniaruckeri

bacteria 2/52 Hemorrhages,inflammation, and death

Golden Shiner Virus virus 2/52 Hemorrhaging, full effects and range of susceptible species unknown

Female golden shiner (left) showing mottled ovary typical of infection with O. ovariae.

Non-target species such as brook stickleback (above) were found mixed in with golden shiners purchased from shops.

Nicholas Phelps

UW Lacrosse BioWeb

3. Angler Survey: How do angler behaviors contribute tothe risk of disease spread?

4. Risk Assessment: What is the actual risk of pathogenintroduction via bait bucket transfer?

Viral hemorrhagic septicemia virus (VHSV) is a serious fish pathogen (above) affecting many bait species.

A. salmonicida was found in 3/52 lots tested and is the causative agent of furunculosis, causing tissue necrosis and lesions as shown on these brown trout (left).

Mohamed Faisal

New Jersey Division of Fish and Wildlife

5. Risk Management: What can be done to reduce thatrisk?

• Using data from the angler survey, information from published literature, and quantitative techniques, we will simulate one year of fishing trips in Minnesota.

• Risk will be measured as the the number of diseased fish that are released into the environment each year in our simulation.