Protocole de comptage des concombres de mer, Cucumaria frondosa (Gunnerus, 1767) sur vidéo sous-marine

In response to the increase in landings of Cucumaria frondosa in Saint Pierre and Miquelon, Ifremer has developed an underwater video surveillance programme to improve knowledge of local populations and assess their biomass, with the aim of proposing a sustainable management plan. Four annual surveys (2021, 2022, 2023, 2025) have been conducted in the archipelago's Exclusive Economic Zone (EEZ). Each survey is based on a renewed sampling plan, using a GoPro camera equipped with two LED lights attached to a modified sea cucumber dredge, enabling standardised videos of the seabed to be acquired. To ensure the rigour and reproducibility of the results, a manual counting and annotation protocol has been put in place. This is based on the visual identification of individuals using specific morphological criteria, such as tentacles, podia and anus, followed by systematic annotation in the videos. Each individual is counted only once, using a method that avoids double counting and allows precise location in the image and video. This protocol thus provides a count of sea cucumbers observed on video, giving an estimate of the abundance of the species in the study area. The data collected contributes to the creation of a database of annotated images, which is useful for developing automated recognition models, and supports scientific stock assessment, which is essential for sustainable resource management.