STUDIES ON THRESHOLD CURRENT DENSITIES FOR CONVULSION OF FISH USING A SQUARE WAVE STIMULATOR

Abstract

The threshold current densities and volltage tensions (body
voltages) between the head and tail for bringing about distinct
reactions in Salmo irideus, Cyprinus Carpio, Tinea tinea,
Gasterosteus aculeatus and Salmo fario were studied. In C. carpio
and T. tinea, absolute current densities required decreased with
increase in length of fish. Threshold current densities for different
reactions of fish increased with rise in water temperature and
conductivity of surrounding medium except in case of T. tinea
where low current densities were sufficient in higher conductivity
of water. Impulse D. C. was superior to continuous D. C.
Better effect was noticed in fishes in lower current densities when
their bodies were parallel to the lines of current conduction.