The goal of the Hippo-ATLAS is to collect observation data on species of seahorse and pipefish along the coasts of Europe and the Mediterranean. This project aims to determine their distribution, to create a photographic database to study and illustrate their variability, and to collect data about their habitat to better understand their lifestyle and their vulnerability. The observation data are collected by divers, fishermen and amateur naturalists. An input tool is available online on the website of Peau-Bleue Association. On 01/01/2011, the database contained about 220 records. This is supplemented annually. In addition to the essential data (species, location, date, observer), the following information can be documented for every observation: gender, size, color, depth, substrate.