ATLAS work package 1& 4 presentation at ATLAS 3rd General Assembly Cold-water corals are important habitat-forming elements in the deep sea, harboring rich biodiversity and having a crucial role in marine biogeochemical cycles. Their ecological importance and high vulnerability to anthropogenic activities and global change have contributed to the classification of the habitats they form as high priority for conservation. However, efficient conservation measures require knowledge of the basic biology and life history of the species, as this is essential for the effective evaluation of their resilience and potential responses to human impacts. While there are several studies on the biology, physiology and ecology of scleractinian reef-building species, other habitat-forming species, such as octocorals, have received little attention. The present study describes basic life history traits of two conspicuous octocoral species of the Azores Archipelago, namely Viminella flagellum and Dentomuricea aff. meteor which form dense coral gardens between depths of 150 and 800 meters. The reproductive biology of the species was studied by histological means providing insights on the sexuality, gametogenic cycle, gamete size and fecundity of the species. Moreover, opportunistic observations and sampling during a spawning event of V. flagellum colonies kept in aquaria allowed records of larval development, size, duration and swimming behaviour. The acquisition of such data is scarce and can highly contribute to the implementation of biophysical models on larval dispersal and connectivity among populations.