The aim of this project is the characterization and identification of adequate habitats for spawning and early stages of development of commercially important cephalopod species, which lay their egg batches in benthic substrates within the Islas Atlánticas de Galicia (PNIA) and Archipiélago de Cabrera (PNAC) National Maritime-Terrestrial Parks. The visual census will be undertaken by diving in transects previously established and delimited according to the different substrates present in these areas, and considering the spawning season of the species studied during two years: quarterly in PNIA and every two weeks in spring and summer in PNAC. Every egg mass will be photographed and situated in a map using a geographic positioning system. Temperature and water samples will be collected using Niskin bottles at the maximum and minimum depths to obtain the main hydrographic parameters (salinity, pH, chlorophyll a y nutrients We will count the number of eggs strings in each transect to test their presence in the following census. The location of spawning areas for the common octopus (Octopus vulgaris), cuttlefish (Sepia officinalis) and common squid (Loligo vulgaris),the identification of temporal variations within the spawning season for each species, as well as the definition of the suitability of the topographic, hydrographic and biological conditions for preferent spawning and settlement habitats (the former only for octopus and cuttlefish), will allow to elaborate a contingence plan to protect and preserve the spawning and early juvenile areas. This is the first time that a similar study is undertaken in European waters and affords the management of fisheries according to an ecosystem approach.