The Mediterranean Sea is home to over 2/3 of the world’s charter boat traffic and hosts an estimated 1.5 million recreational boats. Studies elsewhere have demonstrated marinas as important hubs for the stepping-stone transfer of non-indigenous species (NIS), but these unique anthropogenic, and typically artificial habitats have largely gone overlooked in the Mediterranean as sources of NIS hot-spots. From April 2015 to November 2016, 34 marinas were sampled across the following Mediterranean countries: Spain, France, Italy, Malta, Greece, Turkey and Cyprus to investigate the NIS presence and richness in the specialized hard substrate material of these marina habitats. All macroinvertebrate taxa were collected and identified. Additionally, fouling samples were collected from approximately 600 boat-hulls from 25 of these marinas to determine if boats host diverse NIS not present in the marina. Here, we present data revealing that Mediterranean marinas indeed act as major hubs for the transfer of marine NIS, and we also provide evidence that recreational boats act as effective vectors of spread. From this wide-ranging geographical study, we report here numerous new NIS records at the basin, subregional, country and locality level. At the basin level, we report three NIS new to the Mediterranean Sea (Achelia sawayai sensu lato,Aorides longimerus,Cymodoceaff.fuscina), and the re-appearance of two NIS previously known but currently considered extinct in the Mediterranean (Bemlos leptocheirus, Saccostrea glomerata). We also compellingly update the distributions of many NIS in the Mediterranean Sea showing some recent spreading; we provide details for 11 new subregional records for NIS (Watersipora arcuata,Hydroides brachyacantha sensu latoandSaccostrea glomeratanow present in the Western Mediterranean;Symplegma brakenhielmi,Stenothoe georgiana,Spirobranchus tertaceros sensu lato,Dendostrea folium sensu latoandParasmittina egyptiacanow present in the Central Mediterranean, andW. arcuata,Bemlos leptocheirusandDyspanopeus sayiin the Eastern Mediterranean). We also report 51 new NIS country records from recreational marinas: 12 for Malta, 10 for Cyprus, nine for Greece, six for Spain and France, five for Turkey and three for Italy, representing 32 species. Finally, we report 20 new NIS records (representing 17 species) found on recreational boat-hulls (mobile habitats), not yet found in the same marina, or in most cases, even the country. For each new NIS record, their native origin and global and Mediterranean distributions are provided, along with details of the new record. Additionally, taxonomic characters used for identification and photos of the specimens are also provided. These new NIS records should now be added to the relevant NIS databases compiled by several entities. Records of uncertain identity are also discussed, to assess the probability of valid non-indigenous status.

The study of ecosystem functioning – the role which organisms play in an ecosystem – is becoming increasingly important in marine ecological research. The functional structure of a community can be represented by a set of functional traits assigned to behavioural, reproductive and morphological characteristics. The collection of these traits from the literature is however a laborious and time-consuming process, and gaps of knowledge and restricted availability of literature are a common problem. Trait data are not yet readily being shared by research communities, and even if they are, a lack of trait data repositories and standards for data formats leads to the publication of trait information in forms which cannot be processed by computers. This paper describes Polytraits (http://polytraits.lifewatchgreece.eu), a database on biological traits of marine polychaetes (bristle worms, Polychaeta: Annelida). At present, the database contains almost 20,000 records on morphological, behavioural and reproductive characteristics of more than 1,000 marine polychaete species, all referenced by literature sources. All data can be freely accessed through the project website in different ways and formats, both human-readable and machine-readable, and have been submitted to the Encyclopedia of Life for archival and integration with trait information from other sources.

Several imaging techniques are used in biological and biomedical studies. Micro-computed tomography (micro-CT) is a non-destructive imaging technique that allows the rapid digitisation of internal and external structures of a sample in three dimensions and with great resolution. In this review, the strengths and weaknesses of some common imaging techniques applied in biological and biomedical fields, such as optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy, are presented and compared with the micro-CT technique through five use cases. Finally, the ability of micro-CT to create non-destructively 3D anatomical and morphological data in sub-micron resolution and the necessity to develop complementary methods with other imaging techniques, in order to overcome limitations caused by each technique, is emphasised.

The last annotated checklist of marine polychaetes in Greece was published in 2001. Since then, global taxonomic progress, combined with many new species records for Greece, required a thorough review of the taxonomic, nomenclatural and biogeographic status of the national species list. This checklist revises the status of all extant polychaete species reported from the Greek Exclusive Economic Zone since 1832. The work was undertaken as part of the efforts on compiling a national species inventory (Greek Taxon Information System initiative) in the framework of the LifeWatchGreece Research Infrastructure.This checklist comprises an updated and annotated inventory of polychaete species in Greek waters, compiled from literature reports, online databases, museum collections and unpublished datasets. The list provides information on 836 species-level taxa from Greece, of which 142 are considered questionable. An additional 84 species reported in the past are currently considered absent from Greece; reasons for the exclusion of each species are given. Fourteen species are reported here for the first time from Greek waters. At least 52 species in the present list constitute in fact a complex of cryptic or pseudo-cryptic species. Forty-seven species are considered non-native to the area. In addition to the species-level taxa reported in this checklist, eleven genera have been recorded from Greece with no representatives identified to species level. One replacement name is introduced. For each species, a comprehensive bibliographic list of occurrence records in Greece and the synonyms used in these publications are provided as supplementary material. Where necessary, the taxonomic, nomenclatural or biogeographic status is discussed. Finally, the findings are discussed in the wider context of Mediterranean polychaete biogeography, taxonomic practice and worldwide research progress.