MARINE AQUACULTURE BIOSECURITY:

RISKS, PREDICTION AND MANAGEMENT

24 JULY 2018

TOP OF THE SOUTH MARINE BIOSECURITY, NIWA AND CAWTHRON JOINT WORKSHOP

BARRIE FORREST, JAVIER ATALAH,

PATRICK CAHILL, LAUREN FLETCHER

• 500M/yr green-lipped mussels, salmon &

oysters

• Government and industry agendas for growth

and diversification _ 1 billion target

• Pests and diseases are a significant

impediment:

o Sea-based aquaculture is an “end-of pipe”

recipient of harmful species spread globally by

shipping and other vectors

o Infrastructure provides an environment for harmful

species to flourish, including native organisms

NZ AQUACULTURE OVERVIEW

Pacific oyster racks

Sea-based salmon pens

Mussel longlines

AQUACULTURE HEALTH AND DISEASE

• 2010: Major losses in farmed Pacific oysters

due to ostreid herpes virus (2010)

• 2015: Major losses in farmed flat oysters

(aka “Bluff” oyster) due to parasite Bonamia

ostreae led to closure of Marlborough

Industry

• Uncertain risk to green-lipped mussel

industry GSM in a changing climate

• Emerging issues in farmed salmon (e.g. skin

lesions, Rickettsia-like organisms)

• New MBIE research programme

Derelict Pacific oyster racks

Flat oysters

Skin lesions

MARINE PESTS AND BIOFOULING IN AQUACULTURE

• Biofouling impacts:

o Yield, quality & value

o Infrastructure & industry processes

o Mitigation costs

• Impacts of biofouling globally ca. 5%–

40% of production costs, but:

o Often over-stated

o Poorly quantified

o Highly variable

• Ongoing research at Cawthron to

understand risk and mitigation potential

in NZ

Sabella (fanworm)

Didemnum (sea squirt)

Styela (sea squirt)

Ciona (sea squirt) Undaria (Asian kelp)

Diplosoma (sea squirt)

PROBLEM EXOTICS

PROBLEM NATIVES (OR SPECIES OF UNCERTAIN ORIGIN)

Blue mussels

Cladophora

(horse hair weed) Sea tulips

Triangle barnacles Tubeworms

Hydroid

(mussel beard)

Colpomenia

(bubble weed)

Red algae

Cost component Annual regional cost ($NZ)

Cost from direct production impact on Perna

Loss of Perna spat 115,104

Loss of Perna seed mussels 1,327,083

Loss of Perna crop (mean value from Table 1) 16,285,714

Subtotal cost from production impact on Perna 17,727,901

Cost of managing Mytilus biofouling

Monitoring programme for Mytilus 59,000

Farm maintenance 1,770,833

Seeding and grading (spat, seed & crop) 2,500,000

Harvesting 458,333

Factory sorting 458,333

Factory waste disposal (to landfill) 406,250

Subtotal cost of Mytilus management 5,652,750

Total annual loss for regional industry ($NZ) 23,380,651

IMPACTS: BLUE MUSSELS IN MARLBOROUGH

10% of regional mussel

industry revenue

PREDICTION: FORECASTING BLUE MUSSELS

https://cawthron.shinyapps.io/BMOP/

MANAGEMENT: RISK PATHWAYS AND ON-FARM

• Transfer pathways and movements

of gear, vessels and juveniles

• Mussel & oyster industry pathways

include inter-regional transfers

• Guidance produced by MFA,

AQNZ, MPI

• Shellfish sectors have routine

pathway & on-farm measures

https://www.mpi.govt.nz/dmsdocument/13293/send

MARINE FARMING ASSOCIATION PROCEDURES

Item Description

Floats Floats cleaned on site before being moved to another site

Backbones Backbones cleaned on site

Ropes Ropes high pressure and high volume washed on site, taken to land and cleaned again, then dried in bags on shore for one month before reusing

Vessels Vessels antifouled annually

Seed transfers Ropes are stripped, seed is washed and graded on sites and inspected before re-seeding

Record keeping Stock movements well-documented within industry

Biosecurity reporting MFA developed info sheet on reporting procedures and sample handling protocols, in conjunction with MPI

Education MFA bi-annual on water workshops contain biosecurity education segments

Marine Pest Guide distributed to all MFA members and vessels

Focus on increasing awareness for sourcing vessel and harvesting staff

MFA Policy MFA have a policy to promote good biosecurity practices and support education programmes

TOS Marine Biosecurity Partnership

MFA participation in partnership meetings

Wainui Farms Industry funded surveys on the Wainui sites

“SIMPLE” TOOLS TO ENHANCE EXISTING PRACTICES

• Trialled a range of “simple” treatments:

o Mechanical (e.g. water blasting)

o Immersion/spray (e.g. hot water, brine,

vinegar, chlorine, lime…)

• Feasibility for operational scale application:

o Routine vs reactive

o Risk reduction vs negation

Challenge to find feasible treatments for cultured shellfish

Pest

All

dead

Unhealthy

or dead

Increasing treatment severity

Healthy

Treatmentwindow

Healthy Unhealthy

or dead

Cultured shellfish

Lime dips, Canada

“VINEGAR” TREATMENTS MOST EFFECTIVE

• Acetic acid fast (minutes) and effective at

vinegar concentrations (4%)

• Stable in presence of organic matter

• Handling issues can be overcome

• Operational practicality?

• On-farm vs risk pathways?

Field trials with shellfish spat/seed

NOVEL METHODS FOR ON-FARM MANAGEMENT

• Trialled novel tools:

o Micro-encapsulated toxins (BioBullets)

o Augmentative biocontrol

o Innate antifouling defences

o Novel antifouling compounds & surfaces

• Antifouling compounds the most promising

_ “green” antifouling technologies?

3 months

Biocontrol trials: anemones

Antifouling micropeptides Phytochemical from native

Horopito (polygodial) Algal biotoxins (portimine)

WRAP-UP AND CHALLENGES

• Industry wants to grow, but biosecurity an

increasing handbrake

• Many more potential aquaculture pests

and diseases than currently in NZ

• Pathway management best defence, but

for domestic situation needs:

o Effective/affordable tools

o A multi-stakeholder approach

o National consistency

• On-farm tools for existing/new problems

• Willingness to implement (industry pull)

_ What is the impact?

Recreational boats: a high-risk pathway for

aquaculture