Combined effects of temperature and algal density on the life history characteristics in Brachionus angularis and Keratella Valga

Abstract

Temperature and food density are the most important factors influencing the population dynamics of rotifers. In the present study, the effects of temperature and food concentration on the developmental durations, egg ratio, and life-table demography in Brachionus angularis and Keratella valga were studied at four temperatures (15 °C, 20 °C, 25 °C and 30 °C) and four food levels (0.5 × 106, 1.0 × 106, 2.0 × 106 and 3.0 × 106 cells/mL Scenedesmus obliquus). The results showed significant effects of both temperature and food concentration, independently and interactively on the embryonic development (ED), juvenile period (JP), average lifespan (LS), generation time (T) and intrinsic rate of population increase (rm) in B. angularis, while the ED, life expectancy at hatching (e0), LS, T and rm in K. valga. In all conditions, the number of eggs per female and rm in B. angularis were higher than those in K. valga. These results suggested that B. angularis might be more suitable to mass culture in aquaculture than K. valga, and a potential prey for fish larvae in freshwater aquaculture.

Keywords

• Temperature
• food density
• life history
• rotifer
• Brachionus angularis
• Keratella valga