The ECOMARG research group, whose members are mostly scientists from the Instituto Español de Oceanografía (IEO), was formed in 2002 along with the project of the same name to undertake the integral study of the ecosystem of the Le Danois Bank (locally El Cachucho), an undersea mountain in the Cantabrian Sea of a height rivaling the nearby Picos de Europa. ECOMARG counted on the early support of the General Secretariat for Marine Affairs of Spain’s Ministry of the Environment and Rural and Marine Affairs, which gave it use of the oceanographic vessel Vizconde de Eza. The studies and publications of this multidisciplinary group, comprising geologists, physicists and biologists, have documented the diversity, structure and distribution of the main communities populating El Cachucho and other areas of the Cantabrian Sea, and described numerous species new to science, as well as serving as input to educational and awareness campaigns around the need to protect this oasis of marine biodiversity. The scientific quality of the team’s submissions helped make the case for El Cachucho being proposed by the Ministry of the Environment and Rural and Marine Affairs in 2009 as Spain’s first ever offshore Marine Protected Area (MPA), and for its inclusion in both the OSPAR Network of Marine Protected Areas and Natura 2000. Not only that, the investigation and designation of El Cachucho has served as stimulus to identify and propose new Sites of Community Importance in Spain for listing in the Natura 2000 network.