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KLIMA: ELECTROTAXIS OF TWELVE FISHES <br />C <br />B <br />z <br />a <br />t• <br />~ 4 <br />z <br />0 <br />6 <br />a <br />z <br />~' <br />F <br />x <br />w <br />0 <br />a <br />J <br />1 <br />O <br /> <br />--- - ~ <br />-FISH 71-97 mm 0.7 Vole <br />~~ FlSH > IOlmm <br />1 <br />30 vons <br />I P ]A VoHs <br />i <br />i <br />i <br />I <br />~~ 1.5 Vol le <br />I SPANISH SARD NE <br /> <br /> <br />A!1 <br />PULSES /SEC <br />1611 <br />FIG. 3. Times to swim one lap, percent in tetanus at end of one lap, and optimal <br />response indexes at various pulse rates and voltages for scaled sardine and <br />Spanish sardine. Each plotted value is for an initial lot of 7-22 fish. <br />the electrodes ranging from 15 to 30 v/m. The gra- <br />dientwould decrease slowly to the edge of the plates, <br />where it would drop off more quickly, but the gra- <br />a <br />a <br />w <br />0 <br />3 <br />0 <br />W <br />a <br />I.5 Volts <br />1~ 12~ - ~ - 12 ar. <br />Z InN• m <br />Wxe- e;a <br />Q ~ Z J <br />a z 4 Avsrapa Number of Laps 4~ U <br />~ w <br />I_ ~ a <br />~ 5 IS 25 35 5 55 <br />PULSES /SEC <br />FIC. 4. Times to swim one lap and optimal response <br />indexes for round herring at various pulse rates and <br />voltages. Each plotted value is for an initial lot of 10-15 <br />fish. <br />dient near the edges of this plate would be slightly <br />higher. The electric field in this configuration varies <br />as follows: <br />For parallel plates separated by a distance D <br />~~ 4U <br />F = D v/m (1) <br />where F is the v/m in the field, E is applied voltage. <br />The resistance of sea water between the electrodes is: <br />R-n x D (2) <br />A <br />where n is the resistivity of sea water in ohm-meters, <br />and A is the surface area of electrodes; however, this <br />formula only describes the resistance of the volume <br />of water between the electrodes. Resistance measure- <br />ments from empirical field measurements with paral- <br />lel plates when field fringing was considered) are <br />best described by a value five times less than calcu- <br />lations by Formula (2) (Klima 1970b; W. Seidel and <br />C. Kreutzer personal communication). <br />In comparing the electrode configuration, I <br />assumed the dimensions consisted of two 10 X 10 m <br />plates separated by 20 m ; therefore, <br />__ n x D _ 0.213 x 20 <br />R A x 5 l00 x 5 - 0.0085 ohms; (3) <br />