Photoperiodic Modulation on Growth and Behaviour of the Giant Gourami, Trichogaster fasciata (Bloch and Schneider, 1801)

Özet

The influence of different photoperiods was studied on the growth and behaviour of the giant gourami, Trichogasterfasciata. Fish (weight=1.1g; length=4.36cm) were subjected to photoperiod regimes of 0L:24 D, 8L:16 D, 12L:12 D and16L:8 D for 90 days in triplicates. The growth rate was highest (weight=4g) and lowest (weight=2.36g) in the groupssubjected to 16L: 8D and 0L: 24D photoperiods respectively. The mean body weight and mean total length were significantlyhigher (P 0.05) were not significant in the 16 hours light. Mean valuesof food conversion ratio and condition factor were lowest while various growth parameters were found to be maximum in the16 hours light. 16L:8D photoperiod regime produced pronounced effects on the welfare of giant gourami as shown by thenonintrusive welfare indicators. The photoperiodic signals were found to be capable of modifying the behavioural activitieswhere male aggression related to territory or defence and female selection were reduced in control group. The optimumphotoperiod (16 L: 8 D) was an environmental cue for the better growth, welfare and behaviour.