Effects of Different Wavelengths Lights on Growth of Olive Flounder (Paralichthys olivaceus)

Abstract

Light environment in aquatic habitat is one of the important physical parameters affecting the growth of fish. To investigate the effect of the light on the growth of Olive flounder Paralichthys olivaceus, one of main aquaculture species in Korea, fishes were grown under the illumination of Light emitting diodes (LEDs) of different wavelengths. Four kinds of monochromatic LEDs of red (635 nm), violet (400 nm), green (507.5 nm) and blue (462.5 nm), respectively, together with a white fluorescent control, were tested in this study. Two sets of rearing experiments were carried out with 15 fishes per tank equipped with each LED light. Weight and length of each individual fish used in experiment were measured at the beginning and end of the experiment. Mean weights and lengths of the fish subjected for two sets of experiments were (mean ± SD), respectively. Fish were fed (3% of the body weight) 7.52 ± 0.74g and 9.43 ± 0.32cm commercial feed twice a day. Experiments were conducted for 60 days with the photoperiod of 12 hours of light and 12 hours of darkness. Intensity of lights was controlled at the same level in both set up groups. At the end of the experiment growth was significantly different between groups at p<0.05 in which better growth performance was obtained in green LED and lowest growth performance was obtained in red LED. Fish in red light had high amount of GOT (one of stress parameter in fish) than all other fish in other LEDs. Histological analysis performed on the eyes revealed no toxicological effect as all LEDs with control group had the same ratio of photoreceptor layer thickness to total retina layer thickness.