The U.S. EPA developed a short-term chronic (7-day) toxicity test using the cladoceran, Ceriodaphnia dubia, to evaluate effects of complex effluents on survival and reproduction. A wide variety of synthetic and natural foods have been used to culture and test Ceriodaphnia in different types of water (reconstituted water, well water, and surface water) with highly variable results. GLEC's objective in this study was to evaluate the effects of eight widely used feeding regimens on survival and reproduction of C. dubia in a standard laboratory reconstituted water. The water was supplemented with either bacteria or the micronutrient, selenium, or both, to determine if the addition of these components would significantly improve the survival and reproduction of C. dubia. The eight feeding regimens consisted of three synthetic food suspensions (yeast, trout food, and yeast/trout food/Cerophyl (YTC), three natural algal foods (Selenastrum capricornutum, Ankistrodesmus convolutus and Chlamydomonas reinhardii) and two combination foods (trout food/S. capricornutum and YTC/S. capricornutum). A series of screening and generation tests in laboratory water using the eight regimens were used to rank each regimen according to the survival and reproduction of the animals. If a regimen consistently yielded high survival and reproduction in laboratory water, it was then evaluated in surface and well water to verify its adequacy in water types of differing compositions and quality. Based on the results of this study, a feeding regimen(s) will be recommended that will be adequate for long-term culturing and toxicity testing with C. dubia.
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