Animal releasing devices for deep‐sea ecological studies

Ecological studies and restoration efforts in deep‐sea environments are a priority for international programs aimed at preserving biodiversity and recovering ocean health. These efforts, however, face technical challenges, particularly in the controlled placement of megafauna individuals near the seabed. Traditional methods, such as diving with autonomous breathing equipment, are generally impractical for large‐scale restoration beyond 50 m depth, while releasing organisms at the sea surface leads to high dispersion rates, reducing their chances of reaching the intended location. To address these challenges, we have developed and tested releaser devices equipped with enclosed compartments that mechanically open at a specified distance from the seabed, allowing for precise organism release. We designed and deployed various versions of these devices, each suited for different field applications, including active restoration actions and ecological studies requiring the safe deployment of individuals near the seabed. Technical descriptions of these devices are provided for replication and further adaptation. The devices demonstrated their effectiveness in active restoration efforts, particularly in the mass release of cold‐water corals. Additionally, they facilitated ecological studies involving the acoustic tagging of megafauna, allowing for improved monitoring of their daily and spatial behavior. The proposed animal release devices offer a practical solution for deep‐sea restoration and research, ensuring precise organism deployment at designated depths. Their design enhances efficiency in both marine conservation and scientific investigations.