ABSTRACT 



Theoretical studies are presented of the potential, electric field, and current density for 

 spherical electrodes submerged in a large body of water. The problem of the relationship between 

 the head-to-tail potential and current density in a fish as determined by the relative conductivities of 

 the fish and water is also investigated. 



Preliminary experiments with aholehole (Kuhlia sandvicensis) are described in which were 

 sought the optimum values of current density, pulse frequency, and pulse duration for electrotaxis in 

 a snnall tank. These were found to be 6 .6 ma./cm.^, 10 c . p. s . , and 6 to 8 milliseconds respectively. 



A capacitor discharge apparatus was constructed for use with tuna in a large tank. With this 

 apparatus it was possible to induce electrotaxis in small (50 cm.) yellowfin tuna using a pulse frequency 

 of 20 c.p. s. and current density of 4.0 ma. /cm. ^ . 



