The author has done to see stopping effects of electric fish screen in place of leading net.
Fish materials used were 10 Carassius auratus Goldfish of total length 5.0cm., and 10 Oryzias latipes Japanese Killifish of T. L. 2.5cm. as both live in fresh water, and 12 Sphaeroides niphobles Japanese common puffer T. L. 5-7.0cm. in sea-water.
Two electrodes are set in the upper and lower sides at the center of tank, and were closed alternate electric current of sine wave of 50 cycles regulating its voltage and amperage by transformers. (Fig. 1).
Frequencies of fish individuals pass through the center of tank were compared on cases closed and off the electric current.
The result is in Tables 1-4. which are taken efficiencies of passage and those significancy of stopping effects were judged. (Table 5).
In general, stopping effects of electric current in fresh water is about 50% on better condition, as if sufficiently available. The otherhand, the case of sea-water is about 20% and also, less availability, because it is required several hundreds times of amperage than the case of fresh water.
