Gelatinous Zooplankton in Gotland, Sweden, 2022

Footage was obtained at six sites using a GoPro HERO 5 Black camera towed horizontally over seagrass-dominated soft bottoms at depths of 2.1–6.9 m. The camera, positioned 80–100 cm above the seafloor, captured transects 55 m in length during morning and evening sessions.

Sixty transects were recorded, 10 transects per site, with video durations averaging 4 minutes. Jellyfish abundance was estimated by calculating the volume of water filmed, modeled as a triangular prism based on the camera’s field of view and orientation (perpendicular or tilted 70°). Additional measurements included surface and bottom temperatures, as well as wind speed and direction, retrieved from external sources.