Electricity in Fish Research and Management (eBook)

William (Bill) Beaumont currently works as Senior Fisheries Scientist with the Game & Wildlife Conservation Trust, UK. Bill has covered a wide range of research topics from the effect of afforestation and acidification on upland trout populations to studies on lowland pike home range. Bill has also undertaken joint research projects in France, Lithuania, USA, Greece and Cyprus. Bill has specialized in developing methods and techniques used for fish ecological research including the use of telemetry and electrofishing. Bill has managed a salmon counting facility at East Stoke since 1981 and also runs electric fishing training courses. Bill is currently UK Representative for Smith-Root, a North American Internationally-respected?company, which produces and sells fisheries investigation products, including electrofishing equipment.

Acknowledgements, viii

1 Introduction, 1

2 The history of electricity in fish research, 3

3 Electric fishing, 7

3.1 Health and safety, 13

3.1.1 Electric shock, 14

3.1.2 Drowning, 16

3.1.3 Tripping or falling, 16

3.1.4 Trauma, 16

3.2 General issues, 16

4 Electrical terms, 17

4.1 Circuit, 19

4.2 Voltage, 19

4.2.1 Voltage gradient, 22

4.3 Voltage waveforms, 26

4.3.1 Alternating current, 27

4.3.2 Direct current, 28

4.3.3 Pulsed direct current, 30

4.3.3.1 Pulse frequency, 35

4.3.3.2 Pulse width, 38

4.4 Electrical current, 41

4.5 Power, 42

4.5.1 Power factor, 44

4.6 Resistance and resistivity, 44

4.6.1 Electrode resistance, 47

4.6.2 Kirchoff's Law, 49

4.7 Conductance and conductivity, 51

4.7.1 High?]conductivity water, 52

4.7.2 Low?]conductivity water, 52

4.8 Fish conductivity, 53

4.8.1 Water-fish conductivity ratio, 55

4.8.1.1 Graphic depiction, 57

4.8.1.2 Circuit theory, 57

4.8.1.3 Power Transfer Theory (PTT), 58

5 Electric fishing equipment, 63

5.1 Generators, 64

5.1.1 Use of multiple generators and control boxes, 65

5.2 Control boxes, 66

5.2.1 Generator?]based control boxes, 67

5.2.1.1 Control boxes with no facility to control output, 68

5.2.1.2 Control boxes with limited ability to control output, 68

5.2.1.3 Control boxes where many parameters of the output can be controlled, 70

5.2.2 Battery?]powered control boxes, 71

5.3 Electrodes, 72

5.3.1 Anodes, 73

5.3.1.1 Anode shape, 75

5.3.1.2 Anode size, 77

5.3.1.3 Twin and multiple anodes, 79

5.3.1.4 Anode ergonomics, 81

5.3.2 Pre?]positioned area samplers (PPAS), 82

5.3.3 Point abundance sampling using electricity (PASE), 83

5.3.4 Electric nets, 84

5.3.5 Cathodes, 85

5.4 Hand nets, 87

5.4.1 Banner nets, 90

5.5 Stop nets, 90

5.6 Protective and safety equipment, 92

5.6.1 Waders, 92

5.6.2 Gloves, 92

5.6.3 Other protective clothing, 93

5.6.4 Lifejackets, 93

6 Practical factors affecting electric fishing efficiency, 94

6.1 Manpower requirements, 94

6.2 Streambed: conductivity and substrate type, 95

6.3 Weather, 96

6.4 Water temperature, 96

6.5 Fish size, 97

6.6 Fish species, 98

6.7 Fish numbers, 99

6.8 Water clarity, 100

6.9 Site length, 100

6.10 Water depth, 101

6.11 Site width, 101

6.12 Time of day, 102

7 Electric fishing working techniques, 103

7.1 Operator skill and fishing and processing methods, 103

7.2 Fishing using wading, 106

7.2.1 Wading fishing using boats, 108

7.3 Fishing from boats, 110

7.3.1 Boom?]boats, 111

8 Electric fishing 'best' practice, 116

9 Fish population assessment methods, 122

9.1 Estimating relative abundance, 124

9.2 Estimating actual population size, 126

9.2.1 Capture-mark-recapture estimates (CMRs), 127

9.2.2 Catch depletion estimates, 128

10 Fish barriers, 132

11 Fish counters, 138

12 Electroanaesthesia, 142

13 Fish welfare, 145

13.1 Fish handling, 146

13.2 Stress, 146

13.3 Anaesthesia, 148

13.4 Fish density in holding bins, 151

13.5 Oxygen and carbon dioxide, 153

13.6 Ammonia, 154

13.7 Temperature, 155

13.8 Osmotic balance, 155

13.9 Sensitive or robust fish, 155

13.10 Fish eggs, 156

13.11 Bio?]security, 156

14 Record keeping required, 158

15 Summary, 159

Glossary, 161

References, 166