Combined Effect of Light Regimes and Microalgal Diets on Growth and Production of a Freshwater Cladoceran, Ceriodaphnia quadrangula

One of the freshwater cladocerans is Ceriodaphnia quadrangula. This species can be considered as one of the most suitable live foods because of wide range tolerance to water temperature and light characters as well as its culture using microalgal species. This research aimed to investigate the combined effect of different light regimes and algal diets on growth and production of C. quadrangula. The experimental treatments including 4 light regimes: 4L: 4D (4 hours light: 4 hours dark)، 6L: 6D، 8L: 8D، and12L: 12D، and 2 green mono-algal diets of Scenedesmus quadricauda and Chlorella vulgaris which carried out using completely randomized designs with 6 replicates. Results showed that population density، specific growth rate (SGR) and doubling time (Dt) were significantly different between examined treatments (P<0. 05). The highest mean population density of C. quadrangula fed on S. quadricauda were 1000 ± 50. 9 (Mean ±standard error)، 571. 4± 57. 3، 690. 5 ± 62. 3، and 1000 ± 58. 7 individuals/L in treatments of 4L: 4D، 6L: 6D، 8L: 8D and12L: 12D، respectively، while these treatments using C. vulgaris correspondingly were 1642. 9 ± 46. 0، 2261. 9 ± 72. 2، 1023. 8 ± 75. 0 and 2619. 1 ± 80. 3 ind. L-1 during experiment period. In addition، mean SGR obtained in different treatments had range between 0. 04 to 0. 11 day-1. This research illustrated that C. quadrangula had culture capabilities on different light regimes and algal diets، but culture combined conditions of 12L: 12D and C. vulgaris could be prepared for its better performance.