USER`S MANUAL - Smith-Root
Contents
1. 1 Power Switch 25 amp circuit breaker switch used to turn the input power on and off 2 Power Indicator the red light located next to the power switch indicates the electrofisher is turned on 3 High Voltage Indicator The red light located next to the voltage selector switch indicates that the high voltage has been activated 4 Voltage Selector Switch Selects the output voltage 5 Emergency Shutdown Switch Provides a means for quickly stopping the Electrofisher output 6 Output Mode Selector Switch Selects the output wave shape and frequency 7 Pulse Width Control This adjusts the pulse width in DC output modes 8 Ammeter Shows the current flowing through the water via the electrodes 9 Seconds Counter Records actual shocking time in seconds The counter records one count per second when the output is activated and the timer is turned on 10 Key Switch The key provided must be inserted and turned on before power can be output the electrodes 11 Fuse This 8 amp fuse protects the electrofisher from short circuits and overloads 2 ELECTROFSHERS CONNECTIONS Input Plug The power cord from the generator plugs into this 3 pin connector Remote Foot Switch Plug Foot switches provided are plugged into this 4 pin connector The Key switch and the Emergency Shutdown switch must also be activated to get the output to the electrodes Output plug The anode and cathode output cables are connected to this 2 pin con2. TYPE VI A ELECTROFISHING PRINCIPLES CLARITY AND DEPTH Clarity of the water limits the ease of capturing fish The length of the dip net handles and the visibility of the fish limit the depth of effective electrofishing In general waters over ten feet deep cannot be sampled effectively For daytime fishing polarized sunglasses help in locating stunned fish VEGETATION Aquatic vegetation grows better from certain substrates and can hinder electrofishing by fouling electrodes and entangling stunned fish WATER VELOCITY Electrofishing in flowing water is not as effective as in still water since fish are swept away from the electric field and netting is more difficult Also it is more difficult to see a fish in fast flowing water and operators can loose their footing Flows greater than 5 feet per second usually produce poor electrofishing efficiencies 47 wwwismith root com TYPE VI A USER S GUIDE REFERENCES The following are books research papers and other references on various aspects of electrofishing The ideas and findings presented in them form the basis for much of the current practice in electrofishing 1 Bryan R Cowdell and Richard Valdez 1994 Effects of Pulsed DC Electrofishing on Adult Roundtail Chub from the Colorado River in Colorado North American Journal of Fisheries Management Vol 14 2 L G Cows and P Lamarque 1990 Fishing With Electricity Applications in Freshwa
3. m BOAT SAFETY Ground the generator to the boat hull Be sure that all the metal parts on the boat are bonded to each other electrically Run all cables through electrical conduit or use a heavy duty rubber covered cord recommended for wet locations Make all electrical connections in water tight junction boxes Each dip netter should have his own foot switch to control the output The switch should be wired in series with the emergency off switch of the boat operator When wading with a boat even in shallow water chest waders should be worn An operator may trip end up in a kneeling or sitting position in the water and receive a shock All crew members must be alert Operators who control the power switch must be constantly aware of the netters in the electrical field A TYPE VI A ELECTROFISHING SAFETY Do s 1 Always be sure that all personnel are clear of the electrodes before tuming on the power Know how to administer first aid treatment for electri shock Wear flotation devices Have electrical circuits checked only by qualified technicians Disconnect the power supply when the electrofisher is not in use Don ts Don t electrofish alone Don t continue to electrofish if your boots or gloves get wet inside Don t operate an electrofisher if you have had any prior heart ailments Don t operate generators without covers or screens Don t operate generators
4. Js 2 0m DISTANCE 1 0m 0 5m m a 40 E B E 8 w a 0 2 4 6 8 12 14 13 wwwismith rootcom TYPE USER S GUIDE further producing a 33 volt potential at 1 2 meter But the 10cm anode produces the same potential at only 0 6 meter from the electrode Figure 6 further illustrates the effect of electrode diameter The voltage is applied head to tail to a 20cm long fish The applied voltage is 200 volts with 10cm and 20cm diameter ring electrodes Note that the 20cm electrode reaches out farther producing 7 volts head to tail between 1 0 and 1 2 meter from the electrode as opposed to only 4 volts for the smaller electrode at the same distance Note also that the voltage the fish receives closer to the electrode is less for the larger electrode 100 volts instead of 144 volts Larger electrode thus offers two advantages greater range and lower maximum gradient One drawback is that a larger electrode also has greater circuit loading and thus draws more current for the same voltage twice as much for the double size electrode Thus a larger electrode requires a larger generator This dictates practical upper limit on electrode size for a given generator and water conductivity Except for this limitation the larger the electrode the better the fishing effectiveness and the Current tines Constant voltage lines Gradient 4 Distance Figure 4 The field pattern a
5. and the brain damaged Hence AC electrofishing is only successful with small fish in low conductivity water DIRECT CURRENT Direct Current DC is the term given to electrical current that flows only in one direction The current flows from the negative electrode cathode to the positive electrode anode The reaction of fish to direct current is quite different from their reaction to alternating current The first reaction of the fish is to turn toward the anode and start to swim toward it until it reaches an electrical field strong enough to stun it Being stunned is called galvanonarcosis The severe muscle contractions caused by AC do not occur and the fish recover much faster Mortality rate is much lower with direct current PULSED DIRECT CURRENT Even greater anode attraction is possible with pulsed direct current Pulsed direct current is made by interrupting steady DC with an electronically controlled switch The switch gives several on off pulses per second The number of pulses per second pulse frequency and the on time pulse width have different effects on different species of fish In a pulsed DC field a fish s body flexes with each pulse and returns to normal between pulses This flexing and straightening accentuates the involuntary swimming towards the anode called galvanotaxis Galvanotaxis In pulsed DC a fish s body flexes with each pulse Smith Root Programmable Output Waveforms give you complete cont
6. see through top carry handles 20 L x 10 5 W x 15 5 H 75 Ibs Dimensions Instrument Weight wwwismith rootcom ELECTROFISHING SAFETY SAFE FISHING Electrofishing equipment uses voltages and currents that can be lethal to humans The operators must always keep in mind that the chance of receiving an electrical shock is multiplied in or near water Using an electrofisher is like using a firearm if used properly and with good judgment it is perfectly safe lose respect for it and you can lose your life Electrical equipment used in a moist field environment is always subject to deterioration that could lead to dangerous electrical shock Field equipment is also subjected to vibration and impact during transporting and while in operation Often equipment shared by different crews does not receive proper maintenance or a complete checkout Follow the safety guidelines and use good common sense to handle unforeseen circumstances personnel involved in electrofishing should be taught the fundamentals of electricity and have an understanding of the safety requirements The most important factor in electrofishing efficiency and safety is the trai nd experience of the crew TYPE VI A ELECTROFISHING SAFETY At least two members of the crew should be qualified to administer cardiopulmonary resuscitation As opportunities arise all crew members should attend a course in basic life support training E
7. bouncing into other objects while being transported over rough roads Regularly check the connectors and wires for damage or corrosion ELECTROFSHERS TYPE VI A SPECIFICATIONS SPECIFICATIONS Conductivity Range Input Voltage Voltage Indicators Output Voltage AC Output Voltage DC Output Wave shape Output Wave shape DC Output Frequency AC Pulse Frequency DC Input and Output connectors Input and Output cables Output Power AC Output Power DC Output Current Output Metering Safety Devices 10 1 000 micromhos 120 or 240 volt AC 60 Hz Front panel neon 0 707 V RMS in 117 V steps 1 000 V peak in 167 V steps Sine Wave Fast rise slow decay 60 Hz 60 or 120 pps selection MS environmental 5 heavy packed neoprene jacketed 5 000 watt maximum at 707 V 5 000 watt maximum at 1 000V 10 amp AC or DC 10 amp current meter Hand switch amp foot switch must be operated simultaneously Transformer completely isolates electrofisher output from generator and or boat 25 amp magnetic hydraulic circuit breaker 10 amp fuse 3AG fast blow Thermal switch Isolation Input Circuit Protection Output Circuit Protection Isolation Transformer Timer Displa Mechanical register Timer Rate 1 count per second Timer Accuracy 5 percent Cabinet Construction Heavy duty aluminum welded seams
8. for electrofishing The current passing through a fish decreases as the power flow decreases To get the same response from fish the current can be maintained by either increasing the voltage or by keeping the resistance low If a higher voltage is used up to 1 200 volts may be necessary High voltages create three problems special electrical equipment is required safety is reduced for the operators and conditions are lethal for fish close to electrodes ince can be kept low by increasing the size of the 5 The only limitations to this are the availability of larger electrodes and the weight of electrode that can be handled by the operator HIGH CONDUCTIVITY WATER High conductivity is over 2 000 microSiemens per centimenter If a high voltage is applied most current will flow easily through the water and the fish will hardly be affected The electric current follows the path of least resistance and bypasses the fish completely Therefore use low voltages and high currents Currents as high as 60 amps are common the limiting factor being the rating of the power supply Some brackish water and industrial waste water have conductivities over 10 000 microSiemens per centimenter Here smaller power supplies are unable to deliver enough power to stun fish Waters in this range can only be electrofished effectively with the larger model GPPs The Smith Root 7 5 GPP outputs 62 amps through 8 gauge stranded cables This unit can
9. of electrical current Tough skin has more resistance than tender skin and dry skin more then wet skin But tough dry skin alone does not offer enough protection for electrofishing Rubber lineman s gloves rated 5 000 minimum should always be worn Even while wearing rubber gloves and waders never touch an electrode while the circuit is energized Do not work on the electrical system while the generator is running Do not enter the water while the current is on during boom shocking operations A severe electrical shock from electrofishing gear may result in the need for artificial respiration therefore it is imperative that no one ever works alone Planning For Safety 1 Never electrofish alone A minimum of two properly trained people are required for every electrofishing crew A crew leader shall be appointed for all electrofishing The crew leader is responsible for the safety of the crew and the enforcement of all safety regulations 3 The crew leader and at least one additional crew member shall receive training in cardiopulmonary resuscitation CPR and First Aid 4 All electrofishing personnel shall receive training in fundamentals of electricity and safety 5 Check your electrofisher before each operation to ensure that it is in good working order 6 Turn off your electrofisher before making any connections or part replacements 7 When not in use and when transporting the unit disconnect the power
10. stun large fish in the interface between fresh and salt water For example Striped Bass can be stunned for taking brood stock Theoretically high conductivity could be dealt with by using smaller electrodes but this would reduce the range and also create damaging current densities near the anode FISH CONDUCTIVITY A fish will receive the maximum shock through its body TYPE VI A ELECTROFISHING PRINCIPLES when the conductivity of the water is the same as the conductivity of the fish s flesh Unfortunately this is rarely the case Fish flesh conductivity ranges from 500 to 1 500 microSiemens per centimenter Each species has a different conductivity This affects their susceptibility to electric current Conductivities for some fish species are Trout 1220 microSiemens per centimenter Perch 1 089 microSiemens per centimenter Carp 870 microSiemens per centimenter Grudgeon 814 microSiemens per centimenter E Halsband Vilbert 1967 FISH SIZE Among fish of the same species the larger fish are more sensitive to electrical currents Fish absorb power as a function of body surface area This is important to remember if you are shocking for small fish and large fish are also present The large fish are going to receive a much greater shock than the small fish TEMPERATURE Water conductivity and effective fish conductivity increase with higher temperature Conductivities repo
11. the point of electrical contact asphyxia will result Artificial respiration or cardiopulmonary resuscitation may be necessary To prevent electrical shock all electrical equipment should be carefully inspected before each field operation With all electrical equipment in good operating condition and all insulation junction boxes bonding and connections intact there is much less danger of receiving an electrical shock Preventing Electrical Shock Electricity needs to have a complete electrical circuit in order for current to flow The only way that you can get shocked is if you become the electrical conductor to complete the circuit The current flows from the cathode to the anode through the water The water is the electrical conductor If you touched both the anode and the cathode you would become an electrical conductor and complete the circuit path and get a severe electrical shock If you were to touch only one of the electrodes you would not complete the electrical circuit and not get shocked WARNING Touching any electrode is not recommended Unless all conductive objects you come into contact with are connected to the same electrode you will be shocked to find a current path that is not obvious e g the water or the boat Preventing electrical shock means preventing electrical current from entering and flowing through parts of the body The skin is a partial but variable barrier because it offers resistance to the passage
12. without a spark arrester al m m wwwsmith rooteam TYPE VI A USER S GUIDE Introduction to Electrofishing For many years it has been known that fish react to electric current passed through water Electricity was first used for fishing in 1863 when a British patent was granted Major efforts to apply electricity as a tool in fisheries management did not occur until after 1950 Since then detailed studies have been made on the physiological effects of electricity aquatic organisms RESPONSE OF FISH TO ELECTRICITY To collect fish by electrical means we must create an electrified zone of sufficient amplitude to stun fish In the basic electrofishing circuit shown in Figure 1 current is passed between submerged electrodes A fish between these electrodes forms part of a closed circuit and some current flows through its body The effectiveness of the electrofisher is affected by nine factors voltage electrode shape water conductivity water temperature conductivity of the stream bed fish s distance size species and time in the field If these environmental factors are too far out of line poor electrofishing will result To some extent the effects of changes in water conductivity may be compensated for by changing the output voltage WATER CONDUCTIVITY The conductivity of the water and that of the 45875 flesh are the factors that affect electrofishing
13. For ring electrodes the cross section diameter of the ring material is of little importance If the ratio of cross section diameter to ring radius is held constant resistance varies inversely with ring radius CATHODES In electrofishing it is desirable to have a high voltage gradient around the anode and a low voltage gradient around the cathode TYPE VI A ELECTROFISHING PRINCIPLES Cathode Indentical to anode 600V 6 3kW 0 5m grid cathode 350V 3 7KW 10 2 wire noting cathode 10 32447 Total voltage 298888888858 2 4 6 44 45 Bg Distance tom center of anode meters 1 Figure 8 Variation of voltage for three kinds of anode Figure 8 shows variation of voltage as a function of the distance from the fishing anode for three types of cathode It shows that it is advantageous to have the potential of the water as near as possible to that of the cathode The required voltage is reduced by diminishing the resistance of the cathode field This compensates for the reduced resistance so that the current does not vary The power consumption is directly proportional to the voltage used One advantage of a large cathode is that the risk of accidental electrocution is much reduced A large cathode has very low potential with respect to the soil and the water around it The resistance between the cathode and the water is halved each time the surface of the cathode is doubled For example a 100 square foot cathode w
14. LECTRICAL SHOCK It is the current that passes through the human body that does the damage The voltage is relevant because it is the force that pushes the current through the body Experiments show that 20 to 500 Hz AC current is more dangerous than DC or higher frequencies of AC The voltages used by electrofishing gear cause death by one of three means Ventricular Fibrillation Ventricular fibrillation is uncoordinated contraction of the muscles of the heart The heart quivers rather than beats Electrical current through the chest can cause this condition Once a person goes into ventricular fibrillation the only way to stop the quivering is to use a defibrillator pulse shock to the chest to restore heart rhythm Cardiopulmonary resuscitation may help to keep a victim alive until he can be defibrillated Respiratory Arrest The respiratory center is at the base of the skull Thus shocks to the head can cause the breathing to stop Artificial respiration by the mouth to mouth method should be used in this Asphyxia Asphyxia is caused by contraction of the chest muscles 7 wwwismith root TYPE VI A USER S GUIDE When a current is above a certain level a person cannot let go of an electrically hot wire Currents above this level may not cause ventricular fibrillation but may be enough to cause contraction of the chest muscles If the current is not stopped or the victim is not removed from
15. Power Cable Output Power Cable 15 ft Single Foot Hand Switch Instruction Manual Receipt of shipment Carefully remove electrofisher from its shipping container and examine closely for shipping damage If parts are missing or the unit is damaged notify the transportation company and immediately file a claim for the amount of damage This operator s manual contains important information about the operation and maintenance of your unit We suggest you keep this manual and refer to it when making adjustments or ordering parts Additional copies are available for a nominal charge from Smith Root Inc Record the serial number of your type VI A electrofisher in the space provided below Serial number When ordering parts always quote the electrofisher model and serial number located on the unit s nameplate This is essential to ensure that the correct part is shipped to you ELECTROFISHERS TYPE VI A INTRODUCTION Introduction to the Type VI A The type V1 A is a heavy duty 5kW electrofisher It can be used in large bodies of water like lakes and rivers and in low to medium high conductivity waters 10 to 1000 microsiemens cm3 It can be powered by any 240 volt AC generator and features transformer isolation for safety wwwismith root TYPE VI A USER S GUIDE CONTROL PANEL CAUTION before attempting to operate this equipment be sure to read and follow all A instructions and safety precautions
16. USER S MANUAL 5 Contents Introduction to the Type VI A Type VI A Combo Control panel Connections Electrofishing Safety Preventing Electrical Shock Planning For Safety Backpack Safety Boat Safety Do s amp Don ts Introduction to Electrofishin Types of Current Electrode Desig Field Technique Electrofishing Reference amp Training Materials Operating Procedures Set Up Procedure Electrofishing Procedure Generator Speed Trouble Shooting Overload Protection Thermal Protection General Maintenance URRRRARRWWWNA OS Specifications Items manufactured by companies other than Smith Root carry the original manufacturer s warranty Please contact product manufacturer for return instructions Smith Root Inc manufactured products are covered by one year warranty rt in new condition will be nent include not i 5 and i purchase price but no ess than 20 0 Customers receiving equipment n damaged condition wil be refered t b shipping compe reimbursement m and defective d at 10 of for insurance Rev09 2007 Sri Root Inc Vancouver WA USA WIE TOOL CoM TYPE VI A USER S GUIDE Type VI A Combo Package Includes the Following Quantity Description Line Number Ase VI A Electrofisher Input
17. ailure 4 Connect the remote foot switch to the electrofisher The on off switch is to be used by the electrofisher operator and the foot switch by the netter TYPE VI A CONNECTIONS amp SET UP Type VI A q f Input power Control Output power 3 pin female 4 pin female 2 pin female Above Type VI A Connectors NOTE For greater safety and more flexibility it is recommended that a RCB 6B Junction Box be used in the connecting of electrode devices A RCB 6B can be used in both shore and boat operations Power Source Typical hookup of KCB 61 Electrodes and Electrofisher RCB 6B for Type VI A 08747 wwwismith rootcom TYPE VI A USER S GUIDE BERCTROFISHING PROCEDURE 1 Start the engine on the generator Adjust the Mode Selector Switch to the desired mode It is recommended that you use one of the pulsed DC positions 3 Make sure all personnel are clear of the electrodes 4 Turn on the power switch The power indicator lamp should come on Adjust the Pulse Width Control to approximately 3 5ms a Set the Voltage Selector Switch to the lowest setting Insert the key provided into the Key Switch on the front panel Turn it to the ON position 8 Lift the cover on the Emergency Shutdown switch and move it to the ON position 9 Both operators shoul
18. ariation of potential and gradient Figure 10 illustrates the variation in both voltage and gradient between the electrodes Whenever possible the cathode should be placed in parts of the stream that you do not wish to fish or even in parts completely separated from the stream itself The anode should never be allowed to come close to where the cathode is located Boat Cathodes Many aluminum electrofishing boats use the boat hull as the cathode and the boom electrodes as the anode This is perfectly safe as long as you never come in contact with the anode and complete the electrical circuit The National Safety Council in their data sheet 1 696 85 does not recommend using the boat hull as the cathode but we have yet to hear of any accidents occurring because of it Pulsator Figure 11 Bottom mounted cathode plate on SR 6 Figure 11 shows a Smith Root tote barge designed for stream wading operations Note the large cathode plate attached to the bottom of the fiberglass hull The anode is a pair of ring electrodes about 28cm 11 in diameter mounted on fiberglass poles With this arrangement the resistance of the anode pair is four times the cathode resistance Thus four times as much voltage appears in the anode field as in the cathode field and consequently 80 of the applied voltage appears at each electrode The situation could be further improved by enlarging the cathode but a point of diminishing returns is reached D
19. arothers J P Sharber J C DeVos D A House 1994 Reducing Electrofishing Induced Injury of Rainbow Trout North American Journal of Fisheries Management 14 1 Jeffery C Barnet and Gary D Grossman 1988 Effects of Direct Current Electrofishing on the Mottled Sculpin North American Journal of Fisheries Management Vol 8 ELECTROFISHERS SMITH ROOT 14014 NE Salmon C 1 root com
20. d now activate their control switches The High Voltage indicator lamp should come on You should also see a deflection of the ammeter 10 Adjust the Pulse Width Control and Voltage Selector Switch as necessary Caution Do not adjust the Voltage Selector switch or the Mode Selector switch under load Always turn off the Key Switch or the Emergency Shutdown Switch first Damage to the switches may result from switching under load 11 Experiment to learn what mode settings and voltage settings are best for water conditions and the fish being shocked Read section C for useful data GENERATOR SPEED The generator must be run at proper speed to furnish the electrical power it was built to produce All engines have a tendency to slow down when a load is applied The speed governor tries to hold the speed as near constant as possible but when the electrical load is increased the engine speed will always drop slightly This together with the voltage drop within the generator results in lower voltage loaded than when running unloaded The decrease in engine speed will also affect the output frequency slightly 4 TROUBLE SHOOTING The Type VI A has a long history of reliability in the field but problems can occur The electrofisher has built in protection devices to prevent it from being damaged by overloading and overheating OVERLOAD PROTECTION An overload occurs any time the load on the output is greater than the electrofi
21. ea helps prevent the loss of stunned and frightened fish BOATS Boat electrofishers are used in lakes and in streams that are too deep or swift to wade Boats have the advantage of being able to carry large generators and holding tanks for the stunned fish Electrofishing boats typically have two insulated booms extending from the bow From the end of the booms electrodes hang into the water Usually one boom is used as the anode and the other as the cathode The boat operator guides the boat while the electrofishing crew activates the electrofisher when approaching likely habitat NIGHT FISHING Electrofishing at night with lights is five to ten times more effective than daytime fishing especially in lakes In streams the reflection of the spotlight on the ruffled surface makes the fish difficult to see Boats have flood lights on the bow to attract the fish and to help locate stunned fish SURPRISE Collecting can be enhanced by introducing the element of surprise through intermittent fishing The intensity of the anode s peripheral field often frightens fish causing them to bolt and hide Do not work with the power on continuously but turn it on only in likely habitats Fish can be enticed from under areas of heavy cover or ice by inserting a portable anode turning the power on and withdrawing the anode slowly and smoothly Fish will follow the anode under the influence of galvanotaxis into the open where they can be netted
22. l voltage Zone of Potential Fish Injury Fish close to the anode receive a very high head to tail voltage Most fish injuries occur within half a meter from the anode This is called the Zone of potential fish injury We can minimize the injury by reducing the time the electricity is tumed on Duty Cycle Duty cycle is the percent of on time It is a product of the pulse width and the pulse frequency duty cycle can be lowered in three ways by reducing the pulse width by reducing the pulse frequency or by using gated bursts where the power is off for a ELECTRODE DESIGN 0 0 00 The way in which voltage and current distribute around electrofisher electrodes is complex Figure 4 shows the field pattern created by a pair of closely spaced ring electrodes and the voltage gradient between them Note that the current density and voltage gradient are highest near the electrodes The dimensions of the electrodes are very important in determining the voltage distribution around electrofisher electrodes Figure 5 compares a 10cm and a 20cm ring anode rying 200 volts in open water The cathode dimension is lered to be infinite Note that the 20cm anode reaches out cons period between each burst of pulses Fish close to an anode with much a low duty cycle are far less likely to be injured than with a high duty cycle Fish Attraction to Anode Zone of Potential oho Eus Y pes anataxis Galvanotaxis
23. most The conductivity of water depends on the quantity of dissolved salts and minerals in the water The conductivity of potable waters in the United States ranges from 20 to 2 000 microSiemens per centimenter Sufficient current at realistic power levels will flow through water in this range to electrofish successfully Figure 2 illustrates the field patterns caused by the presence of a fish in water In a no distortion is caused by the presence of the fish In low conductivity water b the distortion of the electric field is such that the voltage near the fish is less than it was before the fish was present The reverse is true in where the water conductivity is more than that of the fish In this case the distortion is caused by the current concentrating in the water surrounding the fish In both b and c not as much power is transferred into the fish s body as in a Voltage Source Water Figure 1 The basic electrofishing circuit Equal conductivities b Fish more conductive Figure 2 I 100mm 4 i Electric field patterns caused by fish c Water more conductive 10 ELECTROFISHERS LOW CONDUCTIVITY WATER Distilled water is a very good insulator It has a conductivity range of 0 5 to 5 0 microSiemens per centimenter If anormal voltage is applied in distilled water very little current will flow Power flow is too low to be effective
24. nd the variation of gradient between two electrodes 14 easier it is on the fish Figure 7 shows that larger electrodes increase the fish collection area The shaded areas have voltage gradient between 0 12 and 1 2 volts per cm and are suitable for electrofishing The applied voltage is 300 volts ELECTRODE BEHAVIOR 1 Larger electrodes have lower resistance need more current at given voltage reach out farther and have lower maximum voltage gradient 10cm 02 os os os 10 i2 Distance from electrode centers meters Figure 5 Comparison of two sizes of anode 20cm 00 02 04 06 08 10 12 Distance from electrode centers meters Figure 6 Comparison of effects of two sizes of anode ELECTROFSHERS 10cm 3 Electrode diameter E 3 80cm Distance from electrode centers meters Figure 7 Larger anodes increase the fishing area m Small electrodes pose a hazard to fish because of high current density and voltage gradient 3 Electrodes placed farther apart use less current but the savings are not large 4 The resistance of an electrode varies in direct proportion to water resistivity RING ELECTRODES 1 Once spacing exceeds 10 radii the distance between electrodes is insignificant The region affected by the electrode is limited to 5 to 10 radii 3 Electrode resistance is primarily dependent on electrode radius and varies in inverse proportion to radius 4
25. nector Pin A goes to the anode and Pin B goes to the cathode The cable connectors on the type VI A are easily distin guished by the number of pins Operating Procedures The following is a short summary of the procedures to set up and operate the Type VI A Electrofisher Be sure to also read the Safety Precautions and the Electrofishing Principles sections before starting the generator Set Up Procedure 1 Connect suitable electrodes to the output cable provided The black wire connects to the cathode and the red wire to the anode Plug the 2 pin connector into the electrofisher 2 Connect the input power cable between the generator and the electrofisher Caution Do not plug an electrofisher that is wired for 240 volts into a 120 volt generator or put an electrofisher that is wired for 120 volt into a 240 volt generator 3 If grounding is called for in local codes or radio interference necessitates it do the following On the shore drive 3 4 or 1 inch pipe into the ground as close to the unit as possible This pipe must penetrate moist earth To this pipe connect a ground clamp and run a No 10 wire from it to the battery negative terminal on the control panel or to the generator ground stud Do not connect to a water pipe or a ground used by radio When used in metal hulled boat ensure that the generator frame is grounded to boat hull This will prevent a shock should you experience an electrical f
26. oubling the cathode size would halve the cathode resistance and give an 8 to 1 ratio between anode and cathode resistance Now 88 of the voltage would appear at the anode This is only an 8 improvement and is not worth the additional physical problems associated with the larger cathode SR 6 field tested with two 28cm anodes and a voltage of 240 volts showed good fishing effectiveness 400 microSiemens per centimenter conductivity with a current of 3 to 4 amperes In lower conductivities of 40 microSiemens per centimenter a current of 1 to 1 5 amp is effective This data may serve as a useful bench mark to judge whether a unit is operating under conditions such that fish should be caught If the electrical performance is close to this reference point and fish are not being caught it is safe to conclude there are few fish in the area 16 ELECTROFISHERS FIELD TECHNIQUES An operator engaged in electrofishing must wade or float depending upon the depth and swiftness of the water WADING In shallow slow moving waters the operators can wade and probe the anode into likely fish habitat Wading upstream eliminates the effects of turbidity caused by bottom sediment Furthermore if collections are for food habitat study stunned prey are not swept downstream and consumed by predators Fish that manage to escape are often captured a short distance downstream Closing a stream with seine nets at each end of the study ar
27. ould need another 100 square foot added to pass from 9 to 4 5 ohm However a cathode larger than 100 square feet would be inconvenient to handle for shore side electrofishing Figure 9 compares small and a large cathodes With a standard grid cathode the anode voltage falls distinctly from 324 to 265 volts when using two anodes However with a very large wire netting cathode efficiency falls only slightly from 324 to 302 volts when using two anodes For shore side operations the cathode surface presents the least resistance when it is divided into several parts placed several meters apart An electrode is more effective when its form is least concentrated For example a 3 x12 strip is more effective than a square of 667 45 wwwismith rootcom TYPE VI A USER S GUIDE Standard 0 5m Large wire rid cathode netting cathode aone btwo cone d two anode anodes anode anodes s 9 ot anode field so between anode and cathode 125 85 s 59 Potential difference vols between cathode and water 126 185 2 between anodeand water 324 285 302 total aso 450 Current amps 36 ss 36 Power kilowatts 162 238 128 215 esis ot te wate in sl cases 1 43t bos Figure 9 Comparison of two sizes of cathode 8 8 Potential Total potential volts 8 8 g 2 4 468 48 E Distance trom senor ot anoda moters Cathode Figure 10 V
28. rol over your electrofisher output This patented method of synthesizing waveforms makes it possible to produce virtually any waveform so you can select the one that is safest for the fish POW allows you to create narrow pulses to achieve the same results as wide pulses Narrower pulses put less power into the water This has three benefits you have less chance of damage to the fish your battery or fuel lasts longer and you can work in very conductive water that overloads conventional electrofishers RESPONSE OF FISH TO DC FIELDS An electric field in water can be considered to have three separate areas The outer peripheral area is a weak field that the fish is indifferent to The next area closer to the electrodes has a stronger electrical field but not enough to stun the fish In this area the involuntary swimming action will occur and the fish will swim towards the anode The innermost area has the strongest electrical field and the fish within it are immobilized Zone of Indifference When electrofishing first starts fish are usually hiding up to three meters away so high power is required to attract them out of hiding But as the fish nears the anode high power can injure it 42 ELECTROFSHERS Voltage across fish Field Intensity V cm 625 Distance from anode 1 2 1 0 TYPE VI A ELECTROFISHING PRINCIPLES 70 1 1 1 0 4 120 1 0 2 As the fish nears the anode it receives a very high head to tai
29. rted for Carp Ed 372 microSiemens centimenter 10 543 microSiemens per centimenter 15 7M microSiemens per centimenter 20 106 microSiemens per centimenter 25 199 microSiemens per centimenter Whitney and Pierce 1957 11 wwwismith rootcom TYPE VI A USER S GUIDE When adjusting the output voltage the major consideration is the power being used This is especially true for battery powered electrofishers Power is equal to the voltage multiplied by the current When figuring the power for an electrofisher the fact that it is usually putting out pulsed DC must be taken into consideration The instantaneous power during a pulse may be quite high but if the electrofisher is only producing pulses at a 25 duty cycle the average power would be approximately 25 of the instantaneous power TYPES OF CURRENT ALTERNATING CURRENT Alternating Current AC is an electrical current in which the direction of current flow reverses a number of times per second In an AC field the fish takes a position transverse to the electrical field lines and attempts to face the anode and cathode successively in rhythm with the AC cycle When the field strength increases tetany occurs and the fish stunned Strong contractions of the body muscles make the fish feel rigid Athigh voltages the larger fish may be killed the muscular contractions being so severe that vertebrae are fractured
30. sher can deliver Common caus of overloads are shorting the output anode to the cathode by touching them together working in water too conductive for the unit working with too high a voltage for the water s conductivity and short circuits within the unit or the cables 8 The Type VI Ais protected from overloads and short circuits by an 8 amp fuse on the output circuit and a 25 amp circuit breaker on the input circuit If the 8 amp fuse blows or the 25 amp circuit breaker kicks off reduce either the Pulse Width or the Voltage Selector to a lower setting Make sure that the anode is not shorted to the cathode THERMAL PROTECTION The greatest limiting factor in a transformer is its ability to dissipate heat Because of weight limitations the transformer in the Type VI A is air cooled An internal fan is used to cool the transformer but under very heavy load the transformer will eventually get too hot To prevent damage from occurring to the transformer a thermal cut off switch has been installed in the transformer The thermal switch turns off the output while the transformer gets too hot and it won t turn on again until the transformer has been cooled GENERAL MAINTENANCE Store the Electrofisher in a dry room free from extremes of temperature Clean the front panel of the unit with a mild spray on cleaner Protect the unit from continuous vibration and severe impacts Transport it well secured and protected from
31. supply 8 Check that the electrofisher gives an audible signal when there is voltage present at the anode 9 Do not make any field modifications to your electrofisher without written approval from the manufacturer or a qualified electrical engineer 10 Use only dip nets with insulated handles 11 Wear personnel flotation devices 12 Wear lineman s gloves rated 5 000V minimum 13 Never reach into the water in vicinity of an electrode even if rubber gloves are being worn 14 Take frequent breaks Stress and fatigue endanger the crew 15 Practice the quick release system as shown on page C6 ELECTROFSHERS BACKPACK SAFETY Before each operation check that the frame emergency release is in working order and check that the tilt switch shuts off power if the unit is tipped more than 45 Wear hip boots or chest high waders with non skid soles Wear polarized sunglasses to help you detect sub surface hazards and obstacles Beware of turbid water that can hide unseen sub surface obstacles and sudden drop off Shut off your electrofisher before entering or leaving a stream Do not operate an anode pole when carrying a backpack unit weighing more than 20 pounds when in hazardous conditions If you get water in boots waders or gloves stop work immediately and get dry clothing Operate slowly and carefully Footing in most streams is poor and most falls often occur when operators are hurrying Lad
32. ter Fisheries Management Fishing News Books Blackwell Scientific Publications Ltd ISBN 0 85238 167 0 3 L G Cowx 1990 Developments in Electrofishing News Books Blackwell Scientific Publi 0 85238 166 2 4 N G Sharber and S W Carothers 1988 Influence of Electrofishing Pulse Shape on Spinal Injuries in Adult Rainbow Trout North American Journal of Fisheries Management 8 117 122 5 Michael Bozek and Frank J Rahel 1991 Comparison of Streamside Visual Counts to Electrofishing Estimates of Colorado River Cutthroat Trout Fry and Adults North American Journal of Fisheries Management Vol 11 6 D W Novotny and G R Priegel 1971 A Guideline for Portable Direct Current Electrofishing Systems Technical Bulletin No 51 Department of Natural Resources Madison Wisconsin 18 7 D E Snyder and S A Johnson 1991 Indexed Bibliography of Electrofishing Literature Larval Fish Laboratory Colorado State University Fort Collins Colorado 8 M Burridge and G Goodchild 1988 A Bibliography of Electrofishing Ministry of Natural Resources Fisheries Branch Queen s Park Toronto Ontario Canada 9 Alec Maule and Matthew Mesa 1994 Efficacy of Electrofishing to Assess Plasma Cortisol Concentration in Juvenile Chinook Salmon passing Hydroelectric Dams on the Columbia River North American Journal of Fisheries Management Vol 14 10 N G Sharber S W C
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