Effects of different light intensities on growth, survival, reproductive and life span characteristics of Artemia urmiana (Gunther 1890)

Effects of light intensities on growth, survival, reproductive and life span traits of Artemia urmiana were investigated under laboratory conditions. Nauplii of A. urmiana were hatched and raised in 100gL1 at four illuminations including 0, 100, 2000 and 5000lx with 14:10 (light:dark) photoperiod. Mating pairs of mature animals were randomly isolated and reared continuously under similar conditions. The mode and potential of reproduction as well as adult survival shown by each pair were determined throughout their life span. Results showed that percentages of nauplii survival were significantly (P0.05) different at 5000 and 0lx (76.50% compared with 26.25%) respectively. Total number of offspring was highly correlated with the light intensities showing increased numbers at higher light intensities compared with darkness or 100lx. Reproduction mode was relatively affected by various light intensities. Significant (P0.05) differences were found both in reproductive period and life span at different illuminations. Maximum and minimum offspring productions per reproductive day were found at 5000 and 100lx respectively. The relative degree of oviparity increased as the illumination decreased (57.92% compared with 22.65% at 0 and 5000lx respectively). The optimum light intensities appear to be between 2000lx and 5000lx in this study. These findings could probably be useful for mass culture of A. urmiana in indoor or recirculating systems as well as in outdoor systems for intensive cyst and biomass production.