The effect of yellow and red illuminations on the swimming behaviour, mortality and growth rates of yellowfin tuna juveniles (Thunnus albacares)

Research Center for Fishery, Singaraja, 81155 Bali, Indonesia

^* Corresponding author: hutapeaharianto@gmail.com

Abstract

The breeding program for yellowfin tuna has been conducted at the Institute for Mariculture Research and Fisheries Extension (IMRAFE). The production of early juveniles in the nursery facility from egg spawned by reared tuna was unstable; the survival rate from larvae to juvenile sizes of 2.5-3.0 cm was 1-3%. This problem was suspected due to the effect of lighting system. An experiment was conducted indoor in 14 days with tanks under different illuminations, i.e. yellow and red from light emitted diodes (LED) of 3 watts and brightness of 270 lumen. Each tank contained 50 juveniles of 2.5-3.0 cm in total length (TL). The tuna juveniles were fed with fresh whole fish or fish meats, such as milkfish fries, anchovies, or minced fish, six times per day up to satiation. During the experiment, the swimming behaviour of the juveniles were observed, their body lengths were measured, and cases of mortality of the fish were recorded. The swimming activities of the yellowfin tuna juveniles and growth rate under yellow illumination were higher than under red illumination. Between the two different colours of illumination, the survival rates of the juveniles were similar.