Keeping your farm healthy

Marcy Nelson, Acting Director, MDMR Aquaculture DivisionSebastian Belle, Maine Aquaculture Association

www.maine.gov/dmr/

1

Disease : Any condition that disrupts the normal form or function of an animal or plant.

Biosecurity : Tools and methods designed to reduce the risk of introduction and/or spread of pests, pathogens or parasites.

Risk Factors : Anything that increases the likelihood of introduction and/or potential impact of a pest, parasite or pathogen.

Vectors : Any organism that passively carries and/or transmits a disease causing agent.

Fomites : Any object that passively carries and/or transmits a disease causing agent.

• Disease is not just the presence of a pathogen or parasite; it requires some significant impact (i.e. elevated mortality, growth reduction or product quality reduction). Three things necessary for disease: host in compromised physiological condition, environmental conditions conducive to the pathogen or parasite, and the presence of a pathogen or parasite. Diseases may or may not be infectious. 

• Biosecurity is as much a mindset as actual practices.

• Risk Factor:  Risks are probabilities not absolutes. Biosecurity is a form of risk management. A risk can be both something that increases the probability of introduction and/or anything that increases the impact of a pest, parasite or pathogen (PPP) if it does get into a farm. 

• Vectors are biological in nature, such as organisms that are intermediate host or carriers of PPPs. For example, sea lice on salmon are potential carriers of Infectious Salmon Anemia Virus.

• Fomites tend to be physical in nature. Objects that can serve as carriers of PPPs. For example, contaminated equipment.

2

Pests : Organisms that cause a “nuisance” but not disease.

Parasites : Organisms that draw their nourishment from and adversely affect the organism in or on which it resides.

Pathogens : Any microorganism or substance that may cause disease.

Bacteria : single cell, living, varying hardiness, can be treated with drugs, reproduce by division, can be killed with disinfectants.

Virus : Non-living particles, two types, cannot be treated with drugs, reproduce by injecting DNA/RNA into host cells, can be killed with disinfectants.

• Pests: Examples include fouling organisms or organisms that live in or around farms that make operations difficult or could transmit disease, but do not directly cause disease.

• Parasites may be microorganisms, animals, or plants. They often don’t kill the host, but adversely affect them. They may have implications for human and host health.  

• Pathogens; may or may not cause clinical disease. Organisms may be “carriers” without manifesting clinical disease. 

3

PPP life cycles and degree of “infectivity” Infection pressure (level and frequency) Water Quality Animal/Plant Health and Condition Frequency of vector/fomite exposure Production practices Site selection

• Some PPPs are higher risk (i.e. higher likelihood of occurring or higher impact if they do occur) because of their life cycles. For example if a pathogen has a life cycle that requires an intermediate host or a particular temperature or salinity, sites with those conditions would be higher risk sites.  “Infectivity” is the degree of virulence of a PPP and how easy it is for the PPP to attack the farm animals or plants successfully.

• Infection pressure consists of two components: how much of the PPP is close to or moving through the farm and how often that exposure occurs. Risk is highest when the PPP occurs at high levels frequently.

• Water quality influences the condition (stressed or high health) of the animals and plants on the farm.

• Animal or plant condition is a measure of how able they are to resist infective pressure from PPP exposure. High health animals or plants are better at resisting PPP challenges.

• Frequency of exposure to vectors and fomites has a direct impact on risk levels. The higher the frequency the higher the risk.

• Different production practices can impact infection pressure and animal/plant condition 

4

thus impacting the risk of PPP introduction and/or impact levels after PPP introduction. For example moving animals from nursery areas to production sites may risk PPP introduction or lower animal/plant condition if the move is done poorly, stressing the organisms. Grading is another example of a production practice that might impact risk levels. If grading is done when air temperatures are too hot or cold that would increase risk levels.

• Site selection is one of the most important biosecurity tools. Bad sites that have conditions that stress animals/plants or that are close to sources of PPP would all result in higher disease risk.

4

Vertical transmission: parent to offspring Horizontal transmission◦ Direct Organism-organism (both farmed and wild)◦ Indirect Water Vectors Other organisms Flotsam/organic matter People

Fomites Equipment

5

Risk Analysis◦ Identify the hazard and likely pathways of introduction◦ Estimate its frequency and severity if it occurs◦ Identify ways to reduce or “control” the hazard

Risk Control◦ Prevention◦ Control◦ Mitigation

• The primary goal of biosecurity is the cost‐effective management of risks posed by PPPs.

• It is important to focus on prevention and control upfront rather than treatment after the fact.

• Treatment, if available, is expensive.• Treatment options such as antimicrobials are not an option for shellfish.

6

The Department of Marine Resources was established to conserve and develop marine and estuarine resources…

To protect farmed and natural resources in the State of Maine from pests, parasites, and pathogens, MDMR had developed laws and regulations related to biosecurity and aquatic animal health.

12 M.R.S.A, Part 9, §6071: http://legislature.maine.gov/statutes/12/title12sec6071.htmlDMR Regulations Chapter 24: https://www.maine.gov/dmr/laws‐regulations/regulations/documents/Chapter24‐08212018.pdf

7

* Public trust* We’re all in this together* Shared water = Shared PPPs

* Losses of wild and farmed resources

* Economic consequences * Increased production costs* Unpredictable product

• State‐owned marine waters are held in public trust. DMR serves as the trustee to maintain this common resource for the benefit of all. 

• Through the legislature DMR is given the ability to lease public waters to private interests for aquaculture

• Introductions of parasites, pests, and pathogens (PPPs) can have dire consequences to both farmed and wild resources. As a state agency we have an obligation to both our natural resources and the constituents we serve. 

• Everyone in this room is operating in an open system. As a result, the activities of one have the potential to affect many. One person importing diseased animals into a region can trigger an epidemic that results in mortalities and long‐term economic losses for all others in that region.

8

YOU ARE WHAT YOU EAT!

• Aquatic animals and to a lesser extent plants (due to cell wall structure) are uniquely connected to the environment they grow in. The ocean is an “aqueous” solution and so is the “internal solution” of aquatic animals and plants.

• Absorption of stuff dissolved in the ocean by plants and animals is relatively easy and often happens passively with no energy expended. Absorption or diffusion in animals occurs across the gills and in some cases directly across cell walls. In plants absorption and diffusion occurs through “stomata” (openings in the plant tissue) or directly across cell walls.

• Additionally, unlike terrestrial animals, shellfish filter particles contained in the water column. This concept is very important when considering seed sources or the movement of organisms.

9

In-State Options Out-of-State Options *◦ Approved ME hatchery◦ Secondary seed / nursery*◦ Wild spat collection* No Soft, hard, or hen clams

*Permit may be required

◦ Approved hatchery◦ Secondary seed / nursery◦ No algae or urchins

*Permit required

10

Shellfish:◦ Hatcheries – DMR Downeast Institute Mook Sea Farm Muscongus Bay Aq. Running Tide Tech.◦ Secondary Seed Same LPA Health Area

or a permit is required◦ Wild Same LPA Health Area

or a permit is required

Marine Algae:◦ Hatcheries – DMR Atlantic Sea Farms Oceans Balance Sea Green Farms Springtide Seaweed Univ. of New England◦ Wild ◦ All sorus tissue and

seed must originate in Maine waters

Not necessarily…Generally speaking, all seed must come from a Maine hatchery that has been approved by DMR or from the same LPA Health Area in which you are operating. Otherwise, a permit from DMR is required. 

11

When looking into the use of secondary seed sources (i.e. other leases/LPAs) or wild collection you will need to take into consideration the LPA Health Areas in Chapter 2.90: https://www.maine.gov/dmr/laws‐regulations/regulations/documents/Chapter2‐04012019.pdf.

• All wild shellfish stock or seed used for cultivation or grow‐out must originate from within the same Health Area defined under 2.05 (1) (J) as the LPA site.  Once placed in the coastal waters of Maine it is considered “wild” for the purposes of this regulation. 

• Use of wild shellfish stock or seed originating from outside the Health Area of the LPA site will require evidence that the seed or stock is consistent with the species authorized under2.90(4) and may require evidence that the seed or stock is free from disease, and will 

require a permit from DMR. 

12

REMEMBER: YOU ARE WHAT YOU EAT!

• Evaluation of seed sources is based on the risk of introducing disease or invasive/nuisance species.

• As soon as seed is introduced to open (untreated) waters, it is exposed to any parasites, pests, pathogens, toxins, etc. that are in those waters and poses a risk similar to that of wild product.

• Hatcheries have more control and can operate in a semi-closed system by employing options such as filtration, ultraviolet radiation (UV), and chemical treatment of their intake water. Thereby, reducing the potential exposure to PPPs.

13

Protozoan parasite of oysters 1957: Delaware Bay import 90-95% mortality Intermediate host? Favors high temperature

(>20°C) and salinity (>15 ppt) No going back Management: ◦ Limit impact and spread◦ Disease-resistant strains

• MSX was introduced to the east coast of the United States through the import of Pacific oysters to Delaware Bay. It quickly spread, resulting in up to 90‐95% mortality. A couple of years later it had spread to Chesapeake Bay, and along with Dermo (Perkinsus marinus), decimated the oyster populations in the area.

• To date, it is unclear how MSX is spread. The current theory suggests an unidentified intermediate host (vector) is important in the spread of MSX.

• Once introduced to a waterbody, there is no eliminating MSX, particularly if there are wild populations or bottom culture of American oysters.

• We can only manage the impact and spread through limiting movement to other waterbodies and employing disease‐resistant strains.  

14

1983: DMR Survey (Sherburne & Bean, 1991) ◦ 2 oysters-Marsh River, 2 oysters-Piscataqua River (1983)◦ Low levels (2.4%) at Darling Marine Center (1990)◦ Limited mortality

1995: Piscataqua River (Barber et. al., 1997)◦ Epizootic event (25-80% mortality)◦ Low prevalence (% infected) previously ◦ Still present today

Photo D. Bouchard

15

◦ Mild winter followed by warm dry summer ◦ Producers noted increased mortality (up to 90%) ◦ Rutgers: MSX diagnosed by histology Prevalence 5-100% Intensity varied◦ Genetic sequencing: Similar to Barnstable, MA…

• In the Fall of 2010 an epizootic of MSX reached the Damariscotta River.• In response to unexplained mortalities of up to 90%, 7 growers sent samples to Rutgers 

University. • MSX was confirmed through histology, which involves looking at thin section of tissue 

under a microscope and identifying the protozoan cells.• The percentage of animals infected per sample varied by farm, but ranged from 5‐100% 

of sampled animals testing positive. The larger 2008 and 2009  year classes had heavier and more advanced infections than younger animals. This makes sense because older animals filter greater quantities of water and have had longer exposure.

• In response, DMR, UMAINE, and Kennebec River Biosciences initiated a cooperative survey of wild and farmed oyster populations throughout the state in the Fall of 2010 and following spring 2011. At that time results showed MSX was isolated to the Damariscotta River. Based on this information a restricted area was created to limit the spread of this costly parasite.

• Since 2011, MSX has been detected at additional locations and the “Restricted Area” has been expanded…

16

No movement of oysters from “Restricted Areas” to other areas of Maine. Includes wet storage

and flow through. This does not apply to the

purchase of seed from approved hatcheries.

MSX Detections Damariscotta River:

2010-2019 Marsh River: 2013,

2019 Westport Island: 2015

• If you are culturing American oysters within the Chapter 24.10 (4)(F) Restricted Areas you may not:

• Transfer or sell oysters for placement in other waterbodies of the State.• Place oysters in flow through tanks or wet storage in, or discharging to, other 

waterbodies of the State.• A special permit is required for both of these activities and is unlikely to be granted due 

to the risk of spreading MSX.• European oysters (Ostrea edulis) may not be moved anywhere in the state without a 

permit from MDMR, due to concerns about the pathogen Bonamia ostreae. • Please contact me if you have questions or concerns about purchasing seed or gear from 

other growers.

17

What you need to know to protect you and your neighbors.

18

24.03 Prohibited Activity◦ It shall be unlawful to import for introduction or to

introduce into any coastal waters any live marine organisms, whether indigenous or nonindigenous, without a permit issued by the commissioner…

Import: to bring into the State of Maine from outside Maine.

Introduce: to bring into any place subject to the jurisdiction of the State of Maine from any restrictedareas within the State of Maine.◦ Different from Public Health “Restricted Areas”◦ Defined based on the presence of a pathogen, parasite, or

pest of concern (i.e. MSX).

In addition to the seed source restrictions defined in Chapter 2, DMR’s Chapter 24 regulations were developed to manage the risks associated with the importation of live marine organisms. Links to both chapters are provided on the last slide. 

19

24.10 & 24.15 (including, but not limited to) A. the effects of any previous introduction of the

same or a similar species in Maine or other areas; B. the relationship of the species of marine organism

to be introduced with other members of the recipient area ecosystem; and

C. the potential effects of infectious or contagious diseases, pests or parasites that might be associated with the species of marine organism to be introduced upon other members of the ecosystem of the recipient area.

To import (from out of state) or introduce (from the in‐state restricted areas previously described) a permit from DMR is required. When evaluating the potential risks DMR must consider…

Item C is the criterion that is the driving factor for most permit reviews.  Mussels from PEI – concern about invasive tunicates Oysters from other areas along the Atlantic seaboard – MSX/Dermo/Bonamia

exitiosa Clams – Dermo, QPX

20

Seed Regional pathogen

status

Hatchery certification◦ Filtration/UV◦ 3-year health history◦ Biosecurity audits

Health screening

Broodstock Hatchery quarantine Wash eggs and larvae Screen seed Biosecurity Audits

• Following the 2010 MSX event in the Damariscotta River, DMR, with a group of stakeholders from industry and academia, developed the above guidelines with regard to shellfish imports.  This slide was developed with respect to shellfish, but the general principals would apply to other species as well.

• When considering an out‐of‐state hatchery for seed:• Contact DMR EARLY• DMR will need to evaluate:

• The PPPs present in the waters of the source region• The Biosecurity Plan of the hatchery

• Are they treating their intake water?• Do they routinely screen their product for pathogens?• Have they been “disease free” for 3 or more years?• Are they subject to routine biosecurity audits?

• A health report, from an approved diagnostic lab, will also be required for the lot of seed to be imported.

21

Photo D. Morse

22

Clean and Disinfect!◦ Before use and on land

Steps:1. Power wash/scrub2. Let dry ≥24 hours3. Soak in bleach ≥ 30 mins 1 tablespoon of 5.25% sodium

hypochlorite solution/gallon of water

4. Rinse with freshwater5. Air-dry in the sun ≥ 24 hrs

Do not dispose of removed/waste material in waters of the State, compost or landfill only.

Ropes◦ Hard to disinfect, buy new

Photo D. Morse

When purchasing used shellfish production equipment, thorough disinfection before use is strongly recommended, to limit the risks of introduction of disease or invasive species. 

23

“An ounce of prevention is worth a pound of cure.” – Benjamin Franklin

Small investment to prevent vs. widespread cost of disease

Know the rules◦ Chapter 2: http://www.maine.gov/dmr/laws-

regulations/regulations/documents/02_101713.pdf◦ Chapter 24: http://www.maine.gov/dmr/laws-

regulations/regulations/documents/24.pdf When in doubt, please contact me first!◦ Marcy.Nelson@Maine.gov or (207) 633-9502

THANK YOU

24