University of Houston-Victoria 1 article published in JoVE Biology Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions Gen Kaneko1,4, Tatsuki Yoshinaga2, Kristin E. Gribble3, David M. Welch3, Hideki Ushio1 1Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 2School of Marine Biosciences, Department of Marine Biosciences, Kitasato University, 3Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, 4School of Arts and Sciences, University of Houston-Victoria Rotifers are microscopic zooplankton used as models in ecotoxicological and aging studies. Here we provide a protocol for powerful and reproducible measurement of survival time in Brachionus rotifers. Synchronization of culture conditions over several generations is of particular importance because maternal condition affects life history of offspring.