Png-González, LydiaComas-González, RobertCalvo-Manazza, MatíasFollana-Berná, GuillermoBallesteros, EnricDíaz-Tapia, P.Falcón, Jesús M.García Raso, José EnriqueGofas, Serge SalvatorGonzález-Porto, M.López, EduardoRamos Esplá, AlfonsoVelasco, EvaCarbonell, Ana2023-07-142023-07-142023-05-05Png-Gonzalez, L.; Comas-González, R.; Calvo-Manazza, M.; Follana-Berná, G.; Ballesteros, E.; Díaz-Tapia, P.; Falcón, J.M.; García Raso, J.E.; Gofas, S.; González-Porto, M.; et al. Updating the National Baseline of Non-Indigenous Species in Spanish Marine Waters. Diversity 2023, 15, 630. https://doi.org/10.3390/d150506301424-2818http://hdl.handle.net/2183/33326This article belongs to the Special Issue Trends in Marine Non-Indigenous Species in Europe by 2020, and Predictions through Modelling and Horizon Scanning for 2050[Abstract] The introduction of new non-indigenous species (NIS) in Spanish marine waters is addressed under Descriptor 2 of the European Union’s Marine Strategy Framework Directive. National baseline inventories of NIS have been compiled and updated for the three subregions (Western Mediterranean Sea, WMED; Bay of Biscay–Iberian Coast, ABI; Macaronesia, AMA) with data from 1800 to 2021. An overall of 574 species were identified with an alien, cryptogenic, crypto-expanding, or debatable status, mostly invertebrates (~65%) and primary producers (~22%). Of 412 alien species, 80.51% were reported in ABI, 67.82% in WMED, and 66.67% in AMA. Cryptogenic species are more abundant in the WMED (25.25%), compared to AMA (19.77%) and ABI (18.46%). ABI harbors more established species (62.56%) than AMA (45.2%) and WMED (43.56%), contrary to casual records (AMA 31.64%, WMED 23.76%, ABI 13.85%). Invasive species are more abundant (14.36%) in WMED. The ‘transport-stowaway’ pathway accounted for 142 (79.33%), 123 (67.58%), and 169 (85.21%) records in WMED, ABI, and AMA, respectively. The second most common pathway was ‘transport-contaminant’ related to mariculture (~10% of the total), prevalently in ABI with 42 species (23.08%). The Canary Islands stand out for species introduced through oil platforms from throughout the world. ‘Unaided’ was a relevant pathway of secondary introduction into the WMED, particularly of Lessepsian species progressing westwards. Temporal trends in newly introduced species show similar behavior among subregions.engAtribución 4.0 Internacionalhttp://creativecommons.org/licenses/by/4.0/Alien speciesNational NIS inventoriesMediterranean seaNortheast AtlanticDescriptor 2Marine strategy framework directivejournal articleopen access10.3390/d15050630