Ecomeeting: 3D habitat mapping and sutomated video snalysis of the invasive spider crab Percnon gibbesi in the Mediterranean Sea

We present a novel field-based study investigating the spatial ecology and herbivory patterns of the invasive spider crab Percnon gibbesi, a common herbivore in Mediterranean benthic ecosystems. The project integrates advanced technologies to link crab abundance and behavior with algal productivity and benthic habitat characteristics. High-resolution 3D photogrammetry is used to map ~200 m² seafloor areas, providing detailed habitat models. Simultaneously, unintrusive underwater video systems (GoPros) monitor crab behavior over 24-hour cycles in 4 m² plots. Machine learning techniques are employed to automatically detect and annotate crabs in the video data, yielding information on abundance, size, and movement over time. Seasonal sampling (approximately every two months) is conducted to capture temporal trends in crab density and herbivory. This interdisciplinary approach offers new opportunities to understand the dynamics of invasive species and their interactions with habitat complexity and primary production.