Test No. 212: Fish, Short-term Toxicity Test on Embryo and Sac-Fry Stages

         In this Short-term Toxicity Test on Fish Embryo and Sac-Fry Stages, the life stages from the newly fertilized egg to the end of the sac-fry stage are exposed.         The embryo and sac-fry stages of fish are exposed to five concentrations of the test substance dissolved in water. A choice, depending on the nature of the test substance, is possible between a semi-static and a flow-through procedure. The test starts with placing at least 30 fertilised eggs divided equally between at least three replicate test chambers per concentration, and is terminated just before the yolk-sac of any larvae in any of the test chambers has been completely absorbed or before mortalities by starvation start in controls. Lethal and sub-lethal effects are assessed and compared with control values to determine the lowest observed effect concentration and hence the no observed effect concentration. Alternatively, they may be analysed using a regression model in order to estimate the concentration that would cause a given percentage effect. The study report should include: the daily counting of the offspring, the daily recording of the parent mortality, the weekly measurement of oxygen concentration, temperature, and pH values and the determination of the concentrations of test substance. It should also include the observations of abnormal appearance, abnormal behaviour, hatching and survival...      