7116 ‎(2)‎

• UCREFRP Catalog Number: 7116
• Author: Baxter, G. and J. Simon
• Title: Editor
• USFW Year: Series
• USFW - Doc Type: 1970
• Copyright Material: YES

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SPECIFIC CONDUCTIVITY

Fig, 6. Voltage and elTect needed for c1ectrofishing in waters with dilTerent specific conductivities varying between 0 and 1000
(top figure) and between 0 and 100 /lS (bottom) (data for trout from Cuinat, 1967).

nickel steel and aluminium alloys combine
strength and stability with low corrosion (Steroin
et al., 1972).

External factors

The possibility of using electricity for fishing is
due to the fact that aquatic organisms, (both
invertebrates and fishes) are immobilized (elec-
tronarcosis), when the body voltage from nose to
tail exceeds a certain value. With direct current,
the fish will first show a fright response effect
(negative electro taxis) resulting in efforts to
escape the anode. Getting closer to the anode the
fish will be attracted (positive electro taxis) show-

ing fast swimming movements towards the anode
(forced swimming and galvano-taxis). Bringing the
anode very close to the fish, it will be immobilized
(galvanonarcosis ).

The reaction distance depends on:
1) current line density
2) pulse type of electric current
3) fish size and species
4) the position of the fish in relation to the anode.

The current line density is in turn dependent upon
water qualities (above all the specific conduc-
tivity) and the type of equipment used. Roughly
speaking, when fishing with direct current a fish
> 10 cm is repelled at 0.05-0.10 V fcm, attracted