LAUSR

Abstract The movement of brine shrimp (Artemia spp.) was tracked to evaluate the complex interactions upon toxicant intake using a toxicological bioassay. In this study, we present a new method to assess the toxicity of environmental contaminants to Artemia and validate it using mercury as the toxicant model. We developed a multi-object tracking method that can simultaneously quantify the changes in behavioral characteristics of individual Artemia exposed to mercury ions (Hg2+). As the concentration of Hg2+ increased from 200.59 μg/L to 2.0059 g/L, migratory factors such as the rate of movement, the extent of the pathway, and the straightness of trajectory of Artemia tended to reduce. Hormesis was observed at 2.0059 mg/L Hg2+ and the migratory factors of Artemia were significantly increased. Interestingly, hormesis was also observed in the analysis of turning angle distribution. Shrimp moved with a large angle at a high concentration of Hg2+, showing a peculiar trajectory like that of hovering. Similar results were also observed in real seawater samples. In conclusion, the multi-tracking system for the analysis of behavioral endpoints of Artemia can be used as a fast, simple, repeatable, and easily interpretable testing method to provide more information regarding the toxicity of chemical substances.