9491

• UCREFRP Catalog Number: 9491
• Author: Snyder, D. E.
• Title: Electrofishing and Its Harmful Effects on Fish.
• USFW Year: 2003.
• USFW - Doc Type: Denver.
• Copyright Material: NO

22 INFORMATION AND TECHNOLOGY REpORT--2003-0002

Ta ble 1. Reactions of fish in homogeneous fields of direct current. Star (*) indicates that the reaction was observed, em
dash (-) that it was not observed, and blank that it was not studied. Modified from Table I in Lamarque (1967a).

V fern"

Reactions.

"Approximate variation of voltage-gradient thresholds.
bMain reactions are underlined.

Fish facing anode
First reactions"

Jerks of head
Inhibition of swimming
Forced swimming'
Galvanonarcosis
Protonos
Bending of fins
Tetanus ofmaxillaries
Tetanus of gill covers
Quivering of tail, sagittal plane
Pseudo-forced swimming
Tetanus ofbodv. nervous origin
Opistotonos
Tetanus ofbodv. muscular origin
Body pigmentation"
Fish facing cathode

0.10
I
I
1
I
I
I
1
I
I
I
I
1.25

0.10 First reaction"
I Straightening of fins
I Cathodic galvanotaxis
I Halftum towards anode
I Tetanus ofbodv. nervous origin
I Maxillary spasms
1 Opistotonos
1.25 Tetanus ofbodv. muscular origin
Discoloration of body'
Fish first across field

Temporarv anodic curvature
Temporary cathodic curvature'
Sustained anodic curvature
Fin straightening on anode side,
fin bending on cathode side

0.14

0.35

eRo - roussette (Scyliorhinidae); Sk - skate (Rajidae); Ee - eel (Anguilla anguilla; Anguillidae); Ca - common carp
(Cyprinus carpio; Cyprinidae); Gu - gudgeon (Gobio gobio; Cyprinidae); Te - tench (Tinea tinea; Cyprinidae); Go-
golden fish (Cyprinidae ?); Br - brown trout (Salmo trutta; Salmonidae); Ra - rainbow trout (Oncorhynchus mykiss;
Salmonidae); Se - seahorse (Hippocampus sp.; Syngnathidae); Bu - bullhead (Cottus gobio; Cottidae); Su - sunfish
(Lepomis sp. ?; Centrarchidae); Ti - tilapia M (Tilapia mossambica ?; Cichlildae); Dr - dragonet (Callionymus sp.
(Callionymidae); PI- plaice (Pleuronectes platessa; P1euronectidae); So - sole (Solea vulgaris ?; Soleidae).

dFirst reactions of fish facing anode; transient anodic curvature. These reactions occur only at closing the current. They
are thus more concerned with interrupted current (PDC). By contrast, the "first reactions" of fish facing the cathode take
place at the same threshold, no matter what the conditions of potential input are.

eForced swimming. This reaction does not occur with flatfish, which just flatten themselves on the bottom of the tank.
In the case of Callionymus and Hippocampus, this swimming is induced by pectoral or dorsal fins.

fBody pigmentation, discoloration. These reactions were not thoroughly studied.