Introduction to Electrofishing Lisa Harlan Smith-Root, Inc. Lisa Harlan Smith-Root, Inc.
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Transcript of Introduction to Electrofishing Lisa Harlan Smith-Root, Inc. Lisa Harlan Smith-Root, Inc.
Introduction to ElectrofishingIntroduction to Electrofishing
Lisa HarlanSmith-Root, Inc.
Lisa HarlanSmith-Root, Inc.
OutlineOutline
• Electrical Theory• Electrofishing Equipment• Operation and Safety• Applied Electrofishing Methods• Written Exam
• Electrical Theory• Electrofishing Equipment• Operation and Safety• Applied Electrofishing Methods• Written Exam
“What is electrofishing?”“What is electrofishing?”
• The use of electricity to capture, guide, and block the movement of fish.
• An effective biological sampling tool.• When done correctly injury to fish is
minimal.• This requires knowledge.
• The use of electricity to capture, guide, and block the movement of fish.
• An effective biological sampling tool.• When done correctly injury to fish is
minimal.• This requires knowledge.
History of ElectrofishingHistory of Electrofishing
Started in the late nineteenth century.
Became fishery science tool in 1950’s and 60’s.
Technology and knowledge have improved over the years.
There are still many unknowns.
Started in the late nineteenth century.
Became fishery science tool in 1950’s and 60’s.
Technology and knowledge have improved over the years.
There are still many unknowns.
“Why is it Important to be Knowledgeable?”
“Why is it Important to be Knowledgeable?”
• Electrofishers have enough power to kill you.• How many people have been shocked
before?
• Electrofishers have enough power to kill fish.• How many people have seen injured
fish before?
• Electrofishers have enough power to kill you.• How many people have been shocked
before?
• Electrofishers have enough power to kill fish.• How many people have seen injured
fish before?
What is electricity?What is electricity?
The presence or movement of free electrons.
Protons, electrons, and ions Electrofishing is concerned with
electrons and ions.
The presence or movement of free electrons.
Protons, electrons, and ions Electrofishing is concerned with
electrons and ions.
CurrentCurrent
“Free electrons” - flow easily from one ion to another.
6.3 x 1018 electrons/sec = 1 Amp
Amperes or Amps - flow of electric current.
“Free electrons” - flow easily from one ion to another.
6.3 x 1018 electrons/sec = 1 Amp
Amperes or Amps - flow of electric current.
Conductors, Insulators, Semi-conductors
Conductors, Insulators, Semi-conductors
Conductors - Lots of free electronsMetals, particularlyCopperStainless SteelAluminum
Conductors - Lots of free electronsMetals, particularlyCopperStainless SteelAluminum
Conductors, Insulators, Semi-conductors, cont.Conductors, Insulators, Semi-conductors, cont.
Insulators - Substances with very few free electrons, flow of electrons is slow and arduous.
Rubber Dry air Glass Fiber-reinforced plastics Distilled water
Insulators - Substances with very few free electrons, flow of electrons is slow and arduous.
Rubber Dry air Glass Fiber-reinforced plastics Distilled water
Conductors, Insulators, Semi-conductors, cont.Conductors, Insulators, Semi-conductors, cont.
Semi-conductors - Substances that are in-between conductors and insulators.
SiliconSea waterRain waterCity waterGermanium
Silicon and Germanium used in diodes and transistors.
Semi-conductors - Substances that are in-between conductors and insulators.
SiliconSea waterRain waterCity waterGermanium
Silicon and Germanium used in diodes and transistors.
Why is this important?Why is this important?
You need to know where the electricity will flow and
where it won’t flow.
You need to know where the electricity will flow and
where it won’t flow.
Basic Electrical TheoryBasic Electrical Theory
Amperage - current, flow of free electrons
Voltage - electrical pressure
Resistance - amount of blockage or drag resisting the current
Conductivity - the inverse of resistance
Amperage - current, flow of free electrons
Voltage - electrical pressure
Resistance - amount of blockage or drag resisting the current
Conductivity - the inverse of resistance
Ohm’s LawCalculates for Current (Amps).
Ohm’s LawCalculates for Current (Amps).
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Voltage = Current / ConductivityCurrent = Conductivity * VoltageConductivity = Current / Voltage
Voltage = Current / ConductivityCurrent = Conductivity * VoltageConductivity = Current / Voltage
Watt’s Law Calculates for Power (watts).
Watt’s Law Calculates for Power (watts).
Power (watts) = Voltage * Current
and Ohm’s Law states
Current = Voltage * Conductivity
thereforePower = Voltage * Voltage * Conductivity
Power (watts) = Voltage * Current
and Ohm’s Law states
Current = Voltage * Conductivity
thereforePower = Voltage * Voltage * Conductivity
Main Components of the Electrofisher
Main Components of the Electrofisher
1. Power Source2. Control Unit3. Electrodes
1. Power Source2. Control Unit3. Electrodes
Control UnitsControl Units
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BackpackBackpack BoatBoat
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Boat ElectrodesBoat Electrodes
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AnodeAnode
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CathodeCathode
Backpack / Shore-based Electrodes
Backpack / Shore-based Electrodes
AnodesAnodes
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Cathodes Cathodes
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Power SourcesPower Sources
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DirectCurrentDirect
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AlternatingCurrent
AlternatingCurrent
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VoltageVoltage
• The amplitude (or height) of the waveform.
• Measured in volts.• E.g. 120V
• The amplitude (or height) of the waveform.
• Measured in volts.• E.g. 120V
• Catches a lot of fish
• Easy to produce
• Low power loss• High level of
injury
• Catches a lot of fish
• Easy to produce
• Low power loss• High level of
injury
AC
• Catches fewer fish
• Easy to produce• High power
requirement• Low level of
injury
• Catches fewer fish
• Easy to produce• High power
requirement• Low level of
injury
DC
• Catches many fish
• Hard to produce• Mod. power
requirement• Intermediate
level of injury
• Catches many fish
• Hard to produce• Mod. power
requirement• Intermediate
level of injury
Pulsed DC
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Types of Electrical Waveforms
Types of Electrical Waveforms
Pros and ConsPros and Cons
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Burst of Pulses
• Catches many fish
• Hard to produce• Low power
requirement• Indications are
low level of injury
Pulse PeriodPulse Period
• The duration of time for one complete cycle.
• A cycle is measured from the start of one pulse to the start of the next pulse.
• Measurement includes both “on” and “off” times.
• The duration of time for one complete cycle.
• A cycle is measured from the start of one pulse to the start of the next pulse.
• Measurement includes both “on” and “off” times.
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FrequencyFrequency
• The number of pulse periods per second (hertz or Hz.).
• The inverse of pulse period.• 1/pulse period
• The number of pulse periods per second (hertz or Hz.).
• The inverse of pulse period.• 1/pulse period
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Pulse WidthPulse Width
• The duration of “on” time within one pulse period.
• The duration of “on” time within one pulse period.
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Pulse WidthPulse PeriodPulse WidthPulse Period
* 100% = % Duty Cycle* 100% = % Duty Cycle
20 ms40 ms20 ms40 ms
* 100% = * 100% = 50% Duty Cycle50% Duty Cycle
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% Duty Cycle% Duty Cycle
The percentage of “on” time within one pulse period.
Standard Pulse WaveformStandard Pulse Waveform
time
volts
period
width
DEFINITIONS
Pulse width :The length of timethe current is ON
Frequency :Number of pulsesin a second
How do these things affect fish ?
Exploring the Effects on FishExploring the Effects on Fish
Time (ms)
volts
Pulse width :The length of timethe current is ON
The shorterthe on-time, the less poweryou put into the water andinto the fish
NOTE:
5
a
b
1 3
Exploring the Effects on FishExploring the Effects on Fish
Time (ms)
voltsThe fewer thepulses, the
better.Frequency isa major factorin fish injury !!
NOTE:
5
a
b
1 3
Frequency (Hz):Number of pulsesper second
To minimize fish injury:
use lowest pulse width and frequency
To minimize fish injury:
use lowest pulse width and frequency
Time (ms)
51 3
on on
off off
“Duty-cycle” is the percent of on-time“Duty-cycle” is the percent of on-time
Duty-cycle =
“pulse width” X “pulse frequency” (divided by 10)
Duty-cycle =
“pulse width” X “pulse frequency” (divided by 10)
Example:
Pulse width = 4 msFrequency = 20 Hz
Duty-cycle = (4 x 20)/10 = 8%
Pulse width
Frequency
Pulse width = 4 msFrequency = 20 Hz
Duty-cycle = (4 x 20)/10 = 8%
Duty-cycle = 24%
Electric FieldElectric Field
Reynolds, 1996
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• Intense near electrodes
• Dissipates with distance
Power DensityPower Density
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Power Density = Voltage Gradient * Current Density
Power = Voltage * Voltage * Conductivity
Specific Water Conductivity
Specific Water Conductivity
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Conductivity of WaterConductivity of Water
Low Conductivity < 100 S/cm Requires higher voltage.
High conductivity > 1,500 - 2000 S/cm Requires high current.
Power requirement lessens as the conductivity of the water matches the conductivity of the fish.
Conductivity of the water and fish increase as temperature increases.
Low Conductivity < 100 S/cm Requires higher voltage.
High conductivity > 1,500 - 2000 S/cm Requires high current.
Power requirement lessens as the conductivity of the water matches the conductivity of the fish.
Conductivity of the water and fish increase as temperature increases.
Power Transfer TheoryPower Transfer Theory
Reynolds, 1996
ReviewReview
• How do changes in water conductivity affect power requirements?
• How do changes in fish conductivity affect power requirements?
• How do changes in water conductivity affect power requirements?
• How do changes in fish conductivity affect power requirements?
Electrofishing EquipmentElectrofishing Equipment
There are a variety of electrofishers systems out there…
There are a variety of electrofishers systems out there…
Backpack electrofishin
g
Backpack electrofishin
g
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Tote-barge electrofishing
Tote-barge electrofishing
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Boat electrofishingBoat electrofishing
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Main Components of the Electrofishing System
Main Components of the Electrofishing System
1. Control Unit2. Power Source3. Electrodes
1. Control Unit2. Power Source3. Electrodes
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Power SourcesPower Sources
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Battery Generator
Function of Control UnitsFunction of Control Units
Accepts input from power source Controls and allows control of the output Instrumentation monitors input and output Has power on/power off control Has connectors for anode and cathode Timers to measure electrofishing time
Accepts input from power source Controls and allows control of the output Instrumentation monitors input and output Has power on/power off control Has connectors for anode and cathode Timers to measure electrofishing time
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2.5, 5.0, 7.5, 9.0 GPP Electrofishers
2.5, 5.0, 7.5, 9.0 GPP Electrofishers
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Produces pulsed forms of AC and DC.
AC at 60Hz, DC at 7.5, 15, 30, 60 and 120 Hz.
Control of pulse width and frequency on DC.
VVP - 15B ElectrofisherVVP - 15B Electrofisher
Produces DC, pulsed DC and AC.
Pulsed DC- Freq 5 - 120Hz, Duty cycle 10-80%.
Burst of Pulses - groups of 3 or 6 at 15 - 120 Hz.
AC - 60 Hz.
LR-24 ElectrofisherLR-24 Electrofisher
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Produces DC, pulsed DC, and Burst of Pulses.
Pulsed DC - Freq 1 - 120Hz, Duty cycle 1 - 99%.
Burst of Pulses - 1 - 1000Hz
Electrodes - Backpack and Shore-based
Electrodes - Backpack and Shore-based
AnodesAnodes
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Cathodes Cathodes
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Boat ElectrodesBoat Electrodes
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AnodeAnode
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CathodeCathode
Important Electrode Parameters
Important Electrode Parameters
• Size• Shape• Condition• Orientation
• Size• Shape• Condition• Orientation
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Anode SizeAnode Size
Reynolds, 1996
Cathode SizeCathode Size
• The cathode should have ~3 times the surface area as the anode.
• The larger surface area decreases the electric field intensity near the cathode.
• The cathode should have ~3 times the surface area as the anode.
• The larger surface area decreases the electric field intensity near the cathode.
Electrode ShapeElectrode Shape
The electric field is affected by the shape of the electrode.
Electrode ConditionElectrode Condition
• Electrolysis of the aluminum occurs over time creating a hard ceramic insulating surface.
• Aluminum electrodes need to be cleaned regularly.
• Netting impedes cleaning (and…).• Stainless steel electrodes do not
oxidize.
• Electrolysis of the aluminum occurs over time creating a hard ceramic insulating surface.
• Aluminum electrodes need to be cleaned regularly.
• Netting impedes cleaning (and…).• Stainless steel electrodes do not
oxidize.
Electrode OrientationElectrode Orientation
• The electric field is affected by the position of the electrodes in relation to each other.
• The closer they are together the more intense the field.
• The electric field is affected by the position of the electrodes in relation to each other.
• The closer they are together the more intense the field.
Four Behavioral ZonesFour Behavioral Zones
1. Fright Zone2. Taxis Zone3. Tetanus Zone4. Kill Zone
1. Fright Zone2. Taxis Zone3. Tetanus Zone4. Kill Zone
Fish Behavior DefinitionsFish Behavior Definitions
Fright/Escape: fish swim away Taxis: Fish swims toward anode Tetany/Narcosis: fish immobilized Kill
Fright/Escape: fish swim away Taxis: Fish swims toward anode Tetany/Narcosis: fish immobilized Kill
Like a puppet on a a string!
Like a puppet on a a string!
• This is taxis.• Lead fish to
netters.• Increase
efficiency. • Decrease injury• Ready to net that
fish… No.
• This is taxis.• Lead fish to
netters.• Increase
efficiency. • Decrease injury• Ready to net that
fish… No.
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Fish InjuryFish Injury
What are the potential injuries to fish?
How can I tell if fish are being injured?
What can I do to reduce fish injury?
What are the potential injuries to fish?
How can I tell if fish are being injured?
What can I do to reduce fish injury?
Potential Fish InjuriesPotential Fish Injuries
Stress Syndrome Hemorrhaging Vertebral Injury Death Egg Viability and Reproductivity
Stress Syndrome Hemorrhaging Vertebral Injury Death Egg Viability and Reproductivity
Stress SyndromeStress Syndrome
Physiological and behavioral changes Acidosis and reduced respiratory
efficiency Can take hours to days to recover If death occurs, it’s usually within a
few hours, and is respiratory failure.
Physiological and behavioral changes Acidosis and reduced respiratory
efficiency Can take hours to days to recover If death occurs, it’s usually within a
few hours, and is respiratory failure.
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Level Two
Level Three
Fish HemorrhagingFish Hemorrhaging
External “Branding”External “Branding”
Caused by capillaries under skin hemorrhaging.
Usually chevron-shaped. Can be long-lasting and be a site for
infection. Likely has internal injuries as well. Unbruised fish might also have internal
injuries. Dark splotches can appear which are
not bruising and will disappear in a short time.
Caused by capillaries under skin hemorrhaging.
Usually chevron-shaped. Can be long-lasting and be a site for
infection. Likely has internal injuries as well. Unbruised fish might also have internal
injuries. Dark splotches can appear which are
not bruising and will disappear in a short time.
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Vertebral InjuryVertebral Injury
Injuries to FishInjuries to Fish
Fisheries Techniques, Chp 8 Slideshow
Death of Fish
Consider filleting dead fish to look for hemorrhaging. Fillet along both sides of spine, looking for bloody spots near spine corresponding to spots on fillet.
Egg Viability and Reproductivity
Not much is known about the effects of electrofishing in this area. Avoid spawning females and active spawning areas.
Factors that Affect Fish Injury
Factors that Affect Fish Injury
1. Settings on the Electrofisher
2. Equipment Choices
3. Electrofishing Technique
1. Settings on the Electrofisher
2. Equipment Choices
3. Electrofishing Technique
Setting Up the Electrofisher
Setting Up the Electrofisher
1. Know conductivity of the water.2. Select a waveform.3. Set a voltage.4. Select a frequency.5. Select the pulse width (or duty
cycle)
1. Know conductivity of the water.2. Select a waveform.3. Set a voltage.4. Select a frequency.5. Select the pulse width (or duty
cycle)
Conductivity of WaterConductivity of Water
Low Conductivity < 100 S/cm Requires higher voltage.
High conductivity > 1,500 - 2000 S/cm Requires high current.
Power requirement lessens as the conductivity of the water matches the conductivity of the fish.
Conductivity of the water and fish increase as temperature increases.
Low Conductivity < 100 S/cm Requires higher voltage.
High conductivity > 1,500 - 2000 S/cm Requires high current.
Power requirement lessens as the conductivity of the water matches the conductivity of the fish.
Conductivity of the water and fish increase as temperature increases.
• Catches a lot of fish
• Easy to produce
• Low power loss• High level of
injury
• Catches a lot of fish
• Easy to produce
• Low power loss• High level of
injury
AC
• Catches fewer fish
• Easy to produce• High power
requirement• Low level of
injury
• Catches fewer fish
• Easy to produce• High power
requirement• Low level of
injury
DC
• Catches many fish
• Hard to produce• Mod. power
requirement• Intermediate
level of injury
• Catches many fish
• Hard to produce• Mod. power
requirement• Intermediate
level of injury
Pulsed DC
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Types of Electrical Waveforms
Types of Electrical Waveforms
Pros and ConsPros and Cons
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Burst of Pulses
• Catches many fish
• Hard to produce• Low power
requirement• Indications are
low level of injury
“What Settings Should I Use?”
“What Settings Should I Use?”
Use the lowest voltage, frequency, and duty cycle combination
that elicits “taxis” but minimizes “tetanus”.
Use the lowest voltage, frequency, and duty cycle combination
that elicits “taxis” but minimizes “tetanus”.
Step 1: Volts
Need enough voltsto get fish to twitch.
If fish twitches and escapes,voltage is high enough!
USFS,Boise ID
A note about voltage….
If you double voltage, power density quadruples.
Power density = (Volts/cm)2 x conductivity
Unpublished Data: Do Not Cite
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Hemorrhage DataHemorrhage Data
Unpublished Data: Do Not Cite
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Vertebral Injury DataVertebral Injury Data
Unpublished Data: Do Not Cite
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Behavior and Vertebral Damage (Frequency)
Behavior and Vertebral Damage (Frequency)
Unpublished Data; Do Not Cite
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% of Marked Fish Showing Vertebral Damage
% of Marked Fish Showing Vertebral Damage
Equipment ChoicesEquipment Choices
Electrodes: size, shape, condition, orientation
Dip Nets: shape, depth and mesh size
Electrofisher: appropriate one for the conditions
Electrodes: size, shape, condition, orientation
Dip Nets: shape, depth and mesh size
Electrofisher: appropriate one for the conditions
Electrofishing TechniqueElectrofishing Technique
• Minimize fish exposure time to electric field.
• Keep distance between electrode & fish consistent (if possible).
• Be quick about netting the fish.
• Minimize fish exposure time to electric field.
• Keep distance between electrode & fish consistent (if possible).
• Be quick about netting the fish.
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“Hey Buddy! Don’t break a sweat!”
Electrofishing Technique, cont.
Electrofishing Technique, cont.
• What would you change?
• Resist “pointing” with anode.
• Reduce exposure.• Site variables?
• What would you change?
• Resist “pointing” with anode.
• Reduce exposure.• Site variables?
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“Hey! That was my fish!”
What would you change?What would you change?
• Safety first.• Water
level/velocity.• Position of
netters.• Differences in
netting techniques.
• Levels of efficiency.
• How deep is still safe?
• Safety first.• Water
level/velocity.• Position of
netters.• Differences in
netting techniques.
• Levels of efficiency.
• How deep is still safe?
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Care of FishCare of Fish
Remove fish immediately from electrical field and into holding buckets.
Avoid netting rocks also. Refresh water frequently or use an
aerator. Work up fish often. If holding fish in netted area make sure
they are always out of electrical field after capture.
Remove fish immediately from electrical field and into holding buckets.
Avoid netting rocks also. Refresh water frequently or use an
aerator. Work up fish often. If holding fish in netted area make sure
they are always out of electrical field after capture.
“What should I do if I observe fish with external
marking?”
“What should I do if I observe fish with external
marking?”
• First, evaluate your technique.• Make adjustments accordingly.
• Second, evaluate your settings.• Make adjustments accordingly.• Reduce frequency.• Reduce duty cycle.• Reduce voltage.
• First, evaluate your technique.• Make adjustments accordingly.
• Second, evaluate your settings.• Make adjustments accordingly.• Reduce frequency.• Reduce duty cycle.• Reduce voltage.
ReviewReview
• List the 3 main components of an electrofisher.
• How does electrode size affect the electric field?
• What are the potential injuries to fish?
• How should you set up an electrofisher?
• List the 3 main components of an electrofisher.
• How does electrode size affect the electric field?
• What are the potential injuries to fish?
• How should you set up an electrofisher?
“Why Should I Bother With Safety?”
“Why Should I Bother With Safety?”
All electrofishers have enough power to kill
humans.
All electrofishers have enough power to kill
humans.
Effects of Electrical Current on the Human
Body
Effects of Electrical Current on the Human
Body 1 milliamp Just a faint tingle.
5 milliamps Slight shock felt. Disturbing, but not painful. Most people can “let go”. However, strong involuntary movements can cause injuries.
6-25 milliamps (women)9-30 milliamps (men)
Painful shock. Muscular control is lost. This is the range where “freezing currents” start. It may not be possible to “let go”.
50-150 milliamps Extremely painful shock, respiratory arrest (breathing stops), severe muscle contractions. Flexor muscles may cause holding on; extensor muscles may cause intense pushing away. Death is possible.
1,000-4,300 milliamps(1- 4.3 amps)
Ventricular fibrillation (heart pumping action not rhythmic) occurs. Muscles contract; nerve damage occurs. Death is likely.
10,000 milliamps (10 amps)
Cardiac arrest and severe burns occur. Death is probable.Centers for Disease Control and Prevention, 2002
Life-threatening ConditionLife-threatening Condition
• Cardiac Arrest• Ventricular Fibrillation• Respiratory Arrest
• Lactic Acidosis (delayed onset)
• Cardiac Arrest• Ventricular Fibrillation• Respiratory Arrest
• Lactic Acidosis (delayed onset)
“How Do I Electrofish Safely?”
“How Do I Electrofish Safely?”
1. Training2. Proper Equipment3. Crew Preparation4. Emergency Planning5. Operational Safety
1. Training2. Proper Equipment3. Crew Preparation4. Emergency Planning5. Operational Safety
TrainingTraining
Minimum of two crew members trained in First Aid/CPR particularly as applied to electric shock.
Crew leader, at a minimum, has taken an Electrofishing Course.
Minimum of two crew members trained in First Aid/CPR particularly as applied to electric shock.
Crew leader, at a minimum, has taken an Electrofishing Course.
Proper Equipment - Personal Protection
Equipment
Proper Equipment - Personal Protection
EquipmentRequired1. Non-breathable
Waders or Hip Boots.
2. Non-slip Boots3. Lineman’s GlovesOptional4. PFD or Wading Belt5. Brimmed Hat6. Polarized
Sunglasses
Required1. Non-breathable
Waders or Hip Boots.
2. Non-slip Boots3. Lineman’s GlovesOptional4. PFD or Wading Belt5. Brimmed Hat6. Polarized
Sunglasses
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Proper Equipment - Backpack Electrofisher
Proper Equipment - Backpack Electrofisher
• Tilt Switch• Anode Pole (Power Output) Switch• Audible Signal• Quick Release Harness• Emergency Kill Switch
• Tilt Switch• Anode Pole (Power Output) Switch• Audible Signal• Quick Release Harness• Emergency Kill Switch
Additional Backpack Electrofisher Safety
Features
Additional Backpack Electrofisher Safety
Features• Immersion Sensor• Electrode Out of Water Sensor• Visual Signal (Red Flashing Light)
• Immersion Sensor• Electrode Out of Water Sensor• Visual Signal (Red Flashing Light)
Proper Equipment - Fully Functional
Proper Equipment - Fully Functional
• Inspect equipment before every use. Don’t work with faulty or malfunctioning electrofishing equipment.• Damaged curl cord.• Damaged connectors.• Broken anode pole switch.• Damage strain relief (top of pole).• Dead/broken battery or out of gas.
• Inspect equipment before every use. Don’t work with faulty or malfunctioning electrofishing equipment.• Damaged curl cord.• Damaged connectors.• Broken anode pole switch.• Damage strain relief (top of pole).• Dead/broken battery or out of gas.
Crew PreparationCrew Preparation
• Maintain a crew size of at least 3 preferably 4 people (at least 4 people for shore-based electrofishers).
• Have an assigned crew leader.• Clarify crew leader responsibilities.• Clarify crew responsibilities.
• Maintain a crew size of at least 3 preferably 4 people (at least 4 people for shore-based electrofishers).
• Have an assigned crew leader.• Clarify crew leader responsibilities.• Clarify crew responsibilities.
Crew Preparation - Crew Leader Responsibilities
Crew Preparation - Crew Leader Responsibilities
• Ensure overall crew safety, meet sampling objectives, and monitor welfare of the fish.• Brief all crew on basics of electrofishing, including
dangers and safety requirements.• Have emergency plan in place and communicate it
to all crew members.• Nearest hospital and quickest route to it.• Location of vehicle keys, cell phones, radios and how to
operate them.
• Crew leader is only person to order power on.• Ensure all crew knows anyone can order power off.
• Ensure overall crew safety, meet sampling objectives, and monitor welfare of the fish.• Brief all crew on basics of electrofishing, including
dangers and safety requirements.• Have emergency plan in place and communicate it
to all crew members.• Nearest hospital and quickest route to it.• Location of vehicle keys, cell phones, radios and how to
operate them.
• Crew leader is only person to order power on.• Ensure all crew knows anyone can order power off.
Crew Preparation - Crew Responsibilities
Crew Preparation - Crew Responsibilities
Be trained in basics of electrofishing and safe electrofishing practices.
Be aware of nearest hospital, evacuation route, location of vehicle keys, cell phones, and radios and know how to operate them.
Be alert and attentive, take breaks as necessary.
Communicate with rest of crew. Do not electrofish if you have heart
ailments, wear a pacemaker, or are pregnant.
Be trained in basics of electrofishing and safe electrofishing practices.
Be aware of nearest hospital, evacuation route, location of vehicle keys, cell phones, and radios and know how to operate them.
Be alert and attentive, take breaks as necessary.
Communicate with rest of crew. Do not electrofish if you have heart
ailments, wear a pacemaker, or are pregnant.
Crew Preparation - Crew Communication
Crew Preparation - Crew Communication
• Effective communication between crew members is essential.
• Be sure you know the plan before the electrodes are energized.
• If working in noisy conditions utilize hand signals.
Standardized “Power On” and “Power Off” Signals.• Power On: Patting hand on top of head with
announcement.• Power Off: Slicing the hand across the throat with
announcement. • Hand signals and announcements confirmed by everyone.
• Effective communication between crew members is essential.
• Be sure you know the plan before the electrodes are energized.
• If working in noisy conditions utilize hand signals.
Standardized “Power On” and “Power Off” Signals.• Power On: Patting hand on top of head with
announcement.• Power Off: Slicing the hand across the throat with
announcement. • Hand signals and announcements confirmed by everyone.
Emergency PlanningEmergency Planning
• Prepare and have a plan ahead of time.• Always carry First Aid kit.• In case of accident:• Turn off power to electrofisher and remove it
from the situation.• Evaluate situation and take appropriate
action.• If a person has been shocked they need to
go immediately to nearest hospital.
• Prepare and have a plan ahead of time.• Always carry First Aid kit.• In case of accident:• Turn off power to electrofisher and remove it
from the situation.• Evaluate situation and take appropriate
action.• If a person has been shocked they need to
go immediately to nearest hospital.
Operational SafetyOperational Safety
Never electrofish alone. Minimum of three person crew.
Remove chest strap before entering water. Shut off power before entering or leaving
water. Be sure all crew members are clear of
electrodes before turning power on and before energizing electrodes.
Do not touch electrodes when power is on, not even while wearing Lineman’s gloves.
Turn electrofisher off before connecting or replacing parts.
Never electrofish alone. Minimum of three person crew.
Remove chest strap before entering water. Shut off power before entering or leaving
water. Be sure all crew members are clear of
electrodes before turning power on and before energizing electrodes.
Do not touch electrodes when power is on, not even while wearing Lineman’s gloves.
Turn electrofisher off before connecting or replacing parts.
Operational Safety, cont.Operational Safety, cont.
Operate slowly and carefully to prevent slips and falls.
Electrofish only as far as you can safely wade.
Never electrofish with spectators on shore.
Stop electrofishing immediately if water gets in waders, hip boots, or gloves. Do not resume electrofishing until completely dry.
Operate slowly and carefully to prevent slips and falls.
Electrofish only as far as you can safely wade.
Never electrofish with spectators on shore.
Stop electrofishing immediately if water gets in waders, hip boots, or gloves. Do not resume electrofishing until completely dry.
Crew SafetyCrew Safety
• Accidents happen• Be prepared for
the worst• Safety equipment• Safety procedures
• Accidents happen• Be prepared for
the worst• Safety equipment• Safety procedures
QuickTime™ and aH.263 decompressor
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Crew Safety - Things to Avoid
Crew Safety - Things to Avoid
• Don’t become the conductor.• Don’t touch anything in the
surroundings.• Don’t touch the electrodes.• Don’t use uninsulated dip net handles.• Don’t work without properly
fitting/fully functional personal safety equipment.
• Don’t become the conductor.• Don’t touch anything in the
surroundings.• Don’t touch the electrodes.• Don’t use uninsulated dip net handles.• Don’t work without properly
fitting/fully functional personal safety equipment.
ReviewReview
What are the responsibilities of the crew leader?
How do you electrofish safely?
What are the responsibilities of the crew leader?
How do you electrofish safely?
Applied ElectrofishingApplied Electrofishing
Determine sampling parameters prior to electrofishing: Objectives Amount of effort - distance, time, or
sample size. “Consistency and objectivity”
Determine sampling parameters prior to electrofishing: Objectives Amount of effort - distance, time, or
sample size. “Consistency and objectivity”
Factors that affect Sampling EfficiencyFactors that affect
Sampling Efficiency• Electrodes• Water/ Environmental Conditions• Equipment Settings/ Capabilities• Fish Variables• Human Components
• Electrodes• Water/ Environmental Conditions• Equipment Settings/ Capabilities• Fish Variables• Human Components
Standardized sampling guidelines
Standardized sampling guidelines
Collect all fish possible to avoid bias
Standardize voltage output Pulse rate = 5-40 Hz Duty cycle = 25%
Standardize season - spring or fall Standardize the water stage in
flowing water (not too high or low)
Collect all fish possible to avoid bias
Standardize voltage output Pulse rate = 5-40 Hz Duty cycle = 25%
Standardize season - spring or fall Standardize the water stage in
flowing water (not too high or low)Fisheries Techniques,Chp 8 slideshow
Lake and Pond SamplingLake and Pond Sampling
Use boat electrofisher. Spring and autumn are when
adults tend to be close to shore. Night or twilight are when
predators move inshore. Sample entire shoreline if possible.
If not, more small samples better than few large samples.
Use boat electrofisher. Spring and autumn are when
adults tend to be close to shore. Night or twilight are when
predators move inshore. Sample entire shoreline if possible.
If not, more small samples better than few large samples.
Data analysisData analysis
Species composition Species abundance Population structure Population dynamics - catch
curve/mark-recapture
Species composition Species abundance Population structure Population dynamics - catch
curve/mark-recapture
ReviewReview
• Electrical Theory• Electrofishing Equipment• Operation and Safety• Applied Electrofishing Methods
• Electrical Theory• Electrofishing Equipment• Operation and Safety• Applied Electrofishing Methods
SourcesSources
• Department of Health and Human Services. Electrical Safety: Safety and Health for Electrical Trades. 2002.
• Reynolds, James. Electrofishing. Pages 221- 253. B. R. Murphy and D. W. Willis, editors. Fisheries techniques, 2nd edition. American Fisheries Society, Bethesda, MD. 1996.
• Department of Health and Human Services. Electrical Safety: Safety and Health for Electrical Trades. 2002.
• Reynolds, James. Electrofishing. Pages 221- 253. B. R. Murphy and D. W. Willis, editors. Fisheries techniques, 2nd edition. American Fisheries Society, Bethesda, MD. 1996.
Stream SamplingStream Sampling
Backpack electrofishers good for small streams.
Shore-based or boats for larger streams. Flowing waters limit sampling due to
safety issues. Boat-shock usually downstream, wade
usually upstream. Sample streams methodically with
randomness.
Backpack electrofishers good for small streams.
Shore-based or boats for larger streams. Flowing waters limit sampling due to
safety issues. Boat-shock usually downstream, wade
usually upstream. Sample streams methodically with
randomness.