Zoobooth: A portable, open-source and affordable approach for repeated size measurements of live individual zooplankton

Repeated size measurements of individual animals are valuable for many research questions but can be difficult to obtain without stressing or harming the organism. The authors developed Zoobooth, a video-based, open-source method to size individual live zooplankton with low handling risk and stress. The paper describes construction of a portable instrument to record videos of single animals and a procedure to estimate size from those videos. For Daphnia magna, Zoobooth produced accurate size estimates (correlation to manual measurements ≈ 0.97) and was also tested on other zooplankton taxa. The device is small, portable, inexpensive, and built from readily available components, and can be adapted for studies of coloration or behavior in micro- and macro-plankton. All files to build and use Zoobooth are shared. Highlights: (i) repeated sizing with low handling accidents and stress; (ii) small, portable, affordable device; (iii) simple procedure to optimize parameters for different species.