Typical gatherings observed in the different sites of Lake Geneva before fall/winter 2022-2023: near and inside a wreck, in the water column and near the bottom, in a cavity, and in a pipe. These pictures were extracted from videos that show the quantitative importance of the mysids in typical winter swarms (https://www.youtube.com/watch?v=EuhiGWoyttMandt=11s; https://www.youtube.com/watch?v=KBvkgpm4i5kandt=208s).