DIEL PATTERN OF LOCOMOTOR-ACTIVITY OF ANABAS-TESTUDINEUS UNDER NORMALAND CONSTANT PHOTOPERIOD CONDITIONS

Diel pattern of locomotor activity of climbing perch, Anabas testudine us was recorded by ichthyometer under normal light-dark (L/D--, consta nt light (LL) and constant dark (DD) photoperiod conditions at ambient temperature. Actographs display characteristic circadian rhythm in di ed activity pattern of high and low frequency of activity during scoto phase (night) and photophase (day) respectively. Under artificial cons tant light and dark regimes, fish lost their diel pattern of circadian rhythm of surfacing activity and became arrhythmic, devoid of any fre e-run. Thus, circadian rhythm was not found endogenous but on the cont rary exogenous in nature. The significance of present study may be use ful in fishery management.