Aim: The introduction of aquatic non‐indigenous species (ANS) has become a major driver for global changes in species biogeography. We examined spatial patterns and temporal trends of ANS detections since 1965 to inform conservation policy and management.Location: Global.Methods: We assembled an extensive dataset of first records of detection of ANS (1965–2015) across 49 aquatic ecosystems, including the (a) year of first collection, (b) population status and (c) potential pathway(s) of introduction. Data were analysed at global and regional levels to assess patterns of detection rate, richness and transport pathways.Results: An annual mean of 43 (±16 SD) primary detections of ANS occurred—one new detection every 8.4 days for 50 years. The global rate of detections was relatively stable during 1965–1995, but increased rapidly after this time, peaking at roughly 66 primary detections per year during 2005–2010 and then declining marginally. Detection rates were variable within and across regions through time. Arthropods, molluscs and fishes were the most frequently reported ANS. Most ANS were likely introduced as stowaways in ships’ ballast water or biofouling, although direct evidence is typically absent.Main conclusions: This synthesis highlights the magnitude of recent ANS detections, yet almost certainly represents an underestimate as many ANS go unreported due to limited search effort and diminishing taxonomic expertise. Temporal rates of detection are also confounded by reporting lags, likely contributing to the lower detection rate observed in recent years. There is a critical need to implement standardized, repeated methods across regions and taxa to improve the quality of global‐scale comparisons and sustain core measures over longer time‐scales. It will be fundamental to fill in knowledge gaps given that invasion data representing broad regions of the world's oceans are not yet readily available and to maintain knowledge pipelines for adaptive management.

Evidence so far shows that most alien species (AS) have negative impacts on native biodiversity and are changing biodiversity in almost all environments. Here, we study eight rocky shores at four sites containing reefs with invaded communities and other not-invaded (control) communities, to evaluate the effects of four marine invasive species on biological and functional diversity. We used the adjustment and selection approach of species abundance distribution models (SAD), taxonomic diversity indices and functional diversity indices based on hierarchical grouping matrices (FD—Functional Diversity). In addition to comparing invaded and not-invaded communities, we also performed the same analysis, but removed the invaders (AS removed) from the matrices. The geometric-series model was best adjusted to the majority of communities. The diversity indices suggest that the taxonomic diversity is lower in invaded communities, while the functional diversity indices suggest a change in the functional space of invaded and not-invaded communities, with a greater amount of functional space filled by species in the not-invaded communities. Taxonomic and functional diversity indices were successful in identifying processes that determine the biological diversity of invaded communities, as they seem to obey a pattern that reflects the reduced diversity of invaded communities.

The acidification of samples for the simultaneous measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes represents an important methodological question still not clarified because the removal of calcium carbonate (CaCO3) from samples may affect the outcome of the stable-isotope analysis. We investigated the effect of acidification on samples of 25 different taxa of benthic marine organisms from a rocky shore, to determine whether acidification affects the isotopic values of δ13C and δ15N. After washing with distilled water and drying, each sample was divided into two parts; one part was acidified by adding 1 M HCl with a pipette, until no more CO2 was released, whereas the other part was retained as a non-acidified sample. Organisms with little CaCO3 showed no difference in carbon isotopic signatures after acidification, from those in the non-acidified part. Some organisms with a high CaCO3 content did show differences in carbon isotopic signatures after acidification. The nitrogen isotopic signature presented a significant difference; however, to what extent this difference is biologically important is discussed. Avoiding sampling parts containing a high concentration of carbonate is an efficient way to circumvent this problem. Acidification of samples as a pre-treatment for isotopic analysis is not useful for marine organisms without calcareous structures and is necessary only when the sampled parts contain significant amounts of carbonate.

Considering the potential ecological, socioeconomic, and human health threats related to non-native species introduction, the management of biological invasions is a priority for biodiversity conservation and human welfare. Science-based databases that provide lists and records of non-native species are fundamental to supporting regional and local management actions and decision-making processes. When easily available and disseminated, they can also reach the broader public and foster societal engagement. Here, we describe our experience with the Brazilian Biological Invasion Platform, a portal launched in 2019 that compiles and reports records of estuarine and marine non-native species in Brazil. The system was developed by integrating the Application Programming Interface (API) from Google Maps. Data collation involves four steps: (i) taxon selection; (ii) searches for non-native species reported for Brazil in the scientific literature (including gray literature); (iii) data filtration and extraction to spreadsheets for each species—date, type of record, spatial coordinates, habitat, ecosystem, and source of information; and (iv) careful revision and data transfer to a general database. Finally, the records are uploaded to the platform. The website allows searches by species and by record, with different filters, which are displayed on a map. People and institutions can contribute recommendations, comments, and new records through an online form. The portal encompasses more than 188 non-native and 151 cryptogenic species, with over 6,200 georeferenced records of zoo- and phytoplankton, zoo- and phytobenthos, nekton, and bacteria. We discuss the decision-making process and lessons learned during the first years of the platform, highlighting its impact on management and science outreach, gaps, needs, and challenges, in addition to perspectives for the coming years. Sharing these experiences will contribute to other initiatives already in progress or under development, which constitute important tools to connect biological invasion science, policy, and social awareness.