7711

• UCREFRP Catalog Number: 7711
• Author: Ellis, J. E.
• Title: Survival, growth, and feed conversion of channel catfish after electonarcosis.
• USFW Year: 1973.
• USFW - Doc Type: October 14-17, 1973.
• Copyright Material: YES

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Seventy-five to 100 percent of the fish in the treated lots survived, and from 77
to 100% of the fish in the untreated lots survived. Fish exposed to pulsed direct
current at 25 pulses/see had the lowest survival percentage (75%), but the corres-
ponding control also had a low survival percentage (77%). Fish survival was
affected by dense mats of Pithophora which restricted water exchange between
cages and the open pond. In addition to reduced water exchange, fish were lost
to snake predation and to turtles tearing holes in the wire mesh.
The average sizes of treated and untreated fish were similar. Treated fish
ranged in weight from 205.6 to 312.5 g as compared to the range of 201.6
to 312.5 g for the untreated fish. The lowest average weight of 215.0 g
occurred when pulsed direct current of 15 pulses/see was used.
1.4 to 1.9 in the untreated lots. The better conversion rates (1.4 and 1.6) were in
lots that had low survival. This was probably due to fewer fish per cage.

SUMMARY

Exposure of two-year-o]d catfish to 1.5 volts/ cm' for 60 seconds duration to
either 60 hertz alternating curren!, continuous direct current, or pulsed direct
current did not significantly affect their survival, growth, or feed conversion at
the 0.01 probability ]evel.

LITERATURE CITED

Adams, J. A., D. J. Behmer, and W. O. Weingarten. 1972. Recovery of
shocked common shiner (Notropis cornutus) related to electric energy.
Trans. Amer. Fish. Soc. 101 (3): 552-555..
Hauck, F. R. 1947. Some harmful effects of the electric shocker on large rain-
bow trout. Trans. Amer. Fish. Soc. 77 (I): 61-64.
Maxfield, G. H., R. H. Lander, and K. L. Liscom. 1971. Survival, growth
and fecundity of hatchery-reared rainbow trout after exposure to pu]-
sating direct-current. Trans. Amer. Fish. Soc. 100 (3): 546-552.
McCrimmon, H. R., and B. Bidgood. 1965. Abnormal vertebrae in the rain-
bow trout with particular reference of electrofishing. Trans. Amer. Fish.
Soc. 94 (I): 84-88.
Spencer, S. L. 1967. Jnternalinjuries of largemouth bass and bluegills caused
by electricity. Prog:Fish-Cult. 29 (3): 168-169.

626

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