This dataset assembles historical information existing in public and private documentary archives. Taken together, these data contribute to the building of a knowledge base of the historical presence, extent and biogenic formations of European flat oyster ecosystems prior to and during the intensification of bottom fishing activities. To identify and recover such information requires significant resources and expertise. The establishment of a Historical Ecology Working Group under the umbrella of the Native Oyster Restoration Alliance in early 2020 presented a unique opportunity to coalesce interdisciplinary expertise and resources from multiple European countries to collate and interrogate historical data sources. To date, this is the only known dataset that evidences the past distribution, extent and characteristics of this seabed ecosystem across its full biogeographic range. The described datasets present qualitative and quantitative extracts from written records published between 1524-2022, which show: (1) estimated locations of past oyster fisheries and/or reef habitat across its full biogeographical range, with associated levels of confidence; (2) recorded extent of past reef habitats, and; (3) species associated with these habitats. This comprehensive historical analysis demonstrates that oyster reefs were once a dominant three-dimensional feature along much of the European coastline and some shallow shelf seas.

For the mapping of the turbiditic fans a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m Publication: Ercilla, G., Juan, C., Hernández-Molina, F. J., Bruno, M., Estrada, F., Alonso, B., ... & Ammar, A. (2016). Significance of bottom currents in deep-sea morphodynamics: an example from the Alboran Sea. Marine Geology, 378, 157-170.

For the mapping of the canyon features a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m Publication: Ercilla, G., Juan, C., Hernández-Molina, F. J., Bruno, M., Estrada, F., Alonso, B., ... & Ammar, A. (2016). Significance of bottom currents in deep-sea morphodynamics: an example from the Alboran Sea. Marine Geology, 378, 157-170.

For the mapping of mass-flow deposits a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m

For the mapping of general landslides we analysed and reinterpreted a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m

LIDAR digital surface model, regular grid with 25 mts of spacing between points, from Costa Vicentina coastal area.

LIDAR digital surface model, regular grid with 25 mts of spacing between points, from Vila Real de St. António coastal area.

LIDAR digital surface modelo, regular grid with 25 mts of spacing between points, from Nazare coastal area.

LIDAR digital surface model, regular grid with 25 mts of spacing between points, from Vila Nova de Milfontes coastal area.

LIDAR digital surface model, regular grid with 25 mts of spacing between points, from Faro coastal area.