Efeito dos espectros de luz no desenvolvimento de pós-larvas de Amphilophus citrinellus (Gunther, 1864)

Abstract

Two separate trials were conducted - Trial 1: to evaluate species preference when offered a choice of different spectrum luminosities. Trial 2: to assess the effects of light color and turbidity on the performance and stomach repletion index of Amphilophus citrinellus fry. In Trial 1: 480 fry were distributed into 48 transparent tanks (40 fry per tank) and exposed to four different light spectra: white (688 nm), blue (472 nm), green (436 nm), and red (665 nm). Growth, survival, and stomach repletion index were evaluated at the end of the trial (30 days). In Trial 2: light preference was tested under clear and turbid water conditions. 48 groups of five fish were subjected to associate their location with the spectral stimulus of choice. A tubular arena with doors was set up to allow the fish to choose their preferred location. Results showed that final weight and weight gain were significantly higher in fry raised under blue light (p<0.05), regardless of turbidity. Survival was not affected by light or water condition (p>0.05). The highest stomach repletion index (>75%) was obtained for fish under blue light when exposed to turbid water compared to clear water (p<0.05). Fish under red light and clear water had a higher percentage of stomach repletion than fish in turbid water. When fish were raised under white light, the stomach repletion percentage was higher for animals raised in clear water (p>0.05). No statistical differences were observed in stomach repletion of fry in green light, in clear or turbid water (p>0.05). When given the choice, A. citrinellus preferred blue light in clear water (p<0.05). On the other hand, fish in turbid water preferred white light (p<0.05). These results should be considered when designing rearing protocols for fry in ornamental breeding and trade systems.