Modeling water and small particle residence times in two rearing units used for intensive

culture of steelhead trout Oncorhynchus mykiss in Idaho

Kelly Stockton1, Christine Moffitt1, Tim Allan2, Barnaby Watten3, Brian Vinci4

1USGS: Fish and Wildlife Cooperative Research Unit, University of Idaho 2University of Virginia, 3USGS:

Leetown Science Center, 4Freshwater Institute

Burrows Pond (BP)

Drain

Drain Center Wall

DrainDrain Drain Drain

Mixed-Cell Raceway (MCR)

Velocity Profiles• Velocity measurements collected with a Sontek/YSI

Acoustic Doppler Velocimeter

• Cross-section profiles were measured at 0.3046 and 0.6096 m from surface, in 0.3046 m intervals

Fig. 4: MCR velocity contours and vectors at 0.6096 m depth.

Fig. 3: BP velocity contours and vectors at 0.6096 m depth.

Velocity Profiles

Hydraulic Residence Time• Salt tracer added and measured every minute

at tank discharge

• Concentration normalized and depletion curve analyzed using 95% of the curve to remove the effect of long tails (Levenspiel1979)

Hydraulic Residence Time

• BP and MCR

– Mixed

– Residence time close to ideal

– Few stagnant regions

Particle Removal Efficiency: Bead test• Plastic beads simulate NZMS and infested feces

Particle Removal• MCR: 99% Removal Efficiency

• BP: 6.8% Removal Efficiency

Conclusion• MCR is a better system for rearing fish

• NZMS

– Scouring velocities:

• BP: 8.1 mm

• MCR: 17.03 mm

– Velocities: benthic shear stress:

• ~25 m/s needed to move NZMS

Biosecurity Framework and Methods to Protect Aquaculture

Facilities against Invasive Mollusks

Kelly Stockton1

Christine M. Moffitt2

1Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho2US Geological Survey, Department of Fish and Wildlife, University of Idaho

Aquaculture Facilities and Invasives

• Often constant temperatures

• Constant flows

• Nutrients available

• Transport fish

• Near fishing areas, wildlife reserves and public access

New Zealand mudsnail(Potamopyrgus antipodarium)

• Small→gear

• Operculum

• Parthenogenic reproduction

• High densities

• Shells→Salmonid digestion

High Densities

Operculum

Risk Management• State, provincial, national regulations require

management of invasive species

• HACCP used in many facilities

• Applicable to any operation or species

Reducing and Managing Hazards of Invasive Mollusks in Aquaculture

• Need effective validated monitoring, disinfection and removal tools

• Inconsistent results from multiple, often limited trials

Hatchery Managers Need GuidanceRisk

Assessment

Monitoring

DisinfectionRisk

Management

Removal Tools

Biosecurity Framework and Methods to Protect Aquaculture Facilities

• Evaluate risks and consequences with a framework and decision tree

• Assess the validity of monitoring, disinfection and removal tools

SpringWell

Stream

Effluent

Hatchery

Assessing Tools• Literature search

– Peer review, theses, reports, personal communications

• Ranked criteria: low, medium, high

• Certainty of results analyzed

• Traditional decision treeprocess

RecommendationsAssess Critical Control Points Use tools to lower risk

Choices/ConstraintsPrevention Status Quo Manage Eradicate

Status of FacilityNot Infested Infested

Risk PotentialProbability of Establishment Consequences of Establishment

Risk Assessment and Management

Probability of EstablishmentPathway Evaluation

1. Assessment of Establishment

• Likelihood of pathways

2. Entry Potential

• Likelihood of organism surviving transit in pathway

3. Colonization Potential

• Likelihood of environmental characteristics

4. Passive Spread Potential

• Likelihood of spreading to area

1. Assessment of Establishment and 2. Entry Potential

Pathway

Is your facility affected by

this pathway (yes=1, no=0)

Likelihood of organism

surviving transit in

pathway to area*

Multiply

column

B*C

Anglers

Aquarium trade

Ballast water

Birds and mammals

Boaters

Effluent pond

Field crews

Fish collection

Fish transport

Open water source

Other recreationalists

Visitors

Total Risk for 1&2:

* Determine likelihood based on areas climate or regulations. Ranking: 6= uncertain,

5=very high, 4=high, 3=medium, 2=low, 1= very low

3. Colonization Potential• Stream – Water Body Characteristics

– Flow rate, depth, stream order, elevation, habitat type, substrate type, connectivity

• Water Quality Characteristics

– Season, temperature, specific conductivity, calcium concentration, pH, phosphorus ratios, salinity

• Human Mediated Characteristics

– Disturbance/pollution, angling/stocking, birds

Low Medium High Source

Flow rate >100 cm/sec 70-100 cm/sec <70 cm/sec Holomuzki and Biggs 1999

Certainty Analysis

• All characteristics analyzed

– Lab/field

– Source type

– Endpoint

– Temperature

– Salinity

– Source population

– Location

– pH

– Calculated/ given

– NZMS or other

Source

Lab/

field

Source

type Temp.

Source

population Location

Calculated

/given

Flow Rate

Holomuzki and Biggs

1999 lab

peer

review 19

freshwater

river

New

Zealand calculated

3. Colonization PotentialCharacteristic Ranking Rank # Certainty * Resulting Risk (C*D)StreamFlow Rate

Flow rate- expansion rate

Flow-upstream spread rate

Depth

Stream Order

Elevation

Light Intensity

Habitat type

Substrate type

Connectivity to downstream pop (fish movement)

Average of Stream :

Water QualitySeason

Temperature (max.)a

Optimal Temperature

Temperature (min)a,b

Specific Conductivity

Calcium Concentrationd

pH

Phosphorus ratios

Salinity

Average of Water Quality:

Human MediatedDisturbance

Sediment pollution

Estrogen pollution

Short term N toxicity

Long term N toxicity

Angling/Stocking

Birds/flyway

Average of Human Mediated:

3. Average of risks

# Ranking: 6=uncertain 5=very high, 4=high, 3=medium, 2=low, 1= very low

*Certainty=(.75lab or .90 field)*(source: 0.9 peer reviewed, .8 thesis, .7 report, .6 personal communications)*(1-(tested temp-facility temp)*.1)*(.5 if source

population is different)*(.8calculated or .9 for given)*(.5 if not NZMS)

4. Passive Spread Potential

Known

Population 6-uncertain

5-very

high 4-high 3-medium 2-low 1-very low

Facility

ranking

Distance not known <10 miles

<50

miles

within

state

neighboring

state

not in

country

Density not known >100,000 >10,000 >1,000 >100 >1

4. Total risk ranking

Probability of Establishment

1.&2. Pathways

3. Colonization 4. Spread Risk of

Establishment

Calculated Risk of Establishment Risk Ranking

Uncertain

Very high

High

Medium

Low

Very Low

Consequences of EstablishmentExample risks Ranking level

5. Estimate of economic

impactBased on Federal and State

regulations

6. Environmental effects

potential

Reduction or elimination of

endangered/threatened species

Loss of quality habitat

Increase disease in fish and

bird populations

Reduction in native

biodiversity from less or

elimination of quality

preferred habitat

7. Social and cultural

influences

Can have positive and

negative connotations

(+) increased amount of

decomposition

(-) loss of anglers in region

Total risk:6-uncertain 5-very high 4-high 3-medium 2-low 1-very low

Consequences of Establishment

Calculated Consequences of Establishment Risk Ranking

Uncertain

Very high

High

Medium

Low

Very Low

Risk potential (average of the two)Probability of Establishment Consequences of Establishment

Status of FacilityNot Infested Infested

Risk potential (average of the two)Probability of Establishment Consequences of Establishment

Choices/ConstraintsPrevention Status Quo Manage Eradicate

Status of FacilityNot Infested Infested

Risk potential (average of the two)Probability of Establishment Consequences of Establishment

Choices/Constraints• Determine if facility is infested or not infested

– If not infested choices:• Status Quo• Prevention

– If infested choices:• Status Quo• Manage • Eradicate

– Once facility clean follow not infested choices

• Review of all regulatory constraints– Threatened/endangered– Permits: chemical, transport, etc.– NPDES

RecommendationsAssess Critical Control Points Use tools to lower risk

Choices/ConstraintsPrevention Status Quo Manage Eradicate

Status of FacilityNot Infested Infested

Risk potential (average of the two)Probability of Establishment Consequences of Establishment

Recommendations

• Assess Critical Control Points through HACCP process

• Use tools to lower risk - Prevention

– Different tools will be incorporated at the Critical Control Points to manage or eradicate

• Response Planning and Protocols

Chemical Tools

• Can be used to kill NZMS in foot baths and gear disinfections- closed containers

• Limited research in open water for large scale disinfections

• High environmental contamination risks

• Bath application only, NO SPRAY APPLICATIONS

Certainty Determined By

• Number of replicate trials and temperatures tested

• Replications by different investigators with similar results

• Evaluating presence of neonates

– Stressed adults will release viable neonates

Chemical Certainty

Chemical Certainty

Virkon Aquatic Very High

Sparquat 256 Very High

Formula 409 All Purpose Cleaner Very High

Ammonia High

Copper sulfate High

Pine-Sol High

Formula 409 Degreaser and Disinfectant High

Copper sulfate Medium

Hydrogen Peroxide Medium

Pine-Sol Medium

Benzethonium chloride Medium

Hyamine Medium

Physical Tools• Filtration

– Drum, hydrocyclone, mesh screens, sieves

• Freeze or Heat– Boiling water or fire

• Depuration Strategies• Mixed Cell Raceway• Barriers

– Copper, electrical, velocity, aeration

• Removal– Suction dredge, disturbance-cleaning

Tool Certainty Determined

• For each source

– Percent effective

– Calculated/ given

– Neonates

– Lab/ field

– Type of data

Tool Certainty

Tool Certainty levelHydrocyclone High

Freezers High

Depuration Strategies High

Sieves Medium

Screen Filter Medium

Boiling Water Medium

Fire Medium

Copper Barrier Medium

Drum Filter Low

Mixed Cell Raceway Low

Electrical Barrier Low

Velocity Barrier Low

Aeration Barrier Low

Suction Dredge Low

Disturbance Low

RecommendationsAssess Critical Control Points Use tools to lower risk

Choices/ConstraintsPrevention Status Quo Manage Eradicate

Status of FacilityNot Infested Infested

Risk PotentialProbability of Establishment Consequences of Establishment

Adaptive Process

• New tools for monitoring & disinfection

• New approaches for management

• Validate each tool within target facility

• Applicable to multiple species or facilities

• Be prepared for surprises

Utilization of New Information