This paper is the conclusion of the “Spaghetti Project” aiming to revise French species of Terebellidae sensu lato (s.l.) belonging to the five families: Polycirridae, Telothelepodidae, Terebellidae sensu stricto (s.s.), Thelepodidae and Trichobranchidae. During this project, 41 species were observed, 31 of them new for science: eight species of Polycirridae, eleven species of Terebellidae s.s., three species of Thelepodidae and nine species of Trichobranchidae. We provide a comprehensive key for all European species of terebellids with a focus on the important diagnostic characters for each family. Finally, we discuss issues on taxonomy, biodiversity and cryptic and pseudo-cryptic species of polychaetes in European waters, based on results obtained during this project.

Biological invasions are one of the main global threats to biodiversity in terrestrial, freshwater and marine ecosystems worldwide, requiring effective inventorying and monitoring programs. Here, we present an updated list of non-indigenous species in French marine and transitional waters. Focused on eukaryote pluricellular species found throughout the three metropolitan French marine regions (Western Mediterranean Sea, Bay of Biscay and the Northern Seas), a total of 342 non-indigenous, including 42 cryptogenic, species are listed as having been introduced since the 13th century. The majority of the species originated from the temperate Northern Pacific. They mainly arrived through both ballast and hull fouling and also are associated with shellfish farming activities. Most of them have been introduced since the 1970s, a time when maritime and aquaculture trade intensified. Despite important human-aided opportunities for species transfer between the three marine regions (for instance, via recreational boating or aquaculture transfers), only a third of these NIS are common to all regions, as expected due to their environmental specificities.

The French government is planning the construction of offshore wind farms (OWF) in the next decade (around 2900 MW). Following the European Environmental Impact Assessment Directive 85/337/EEC, several studies have been undertaken to identify the environmental conditions and ecosystem functioning at selected sites prior to OWF construction. However, these studies are generally focused on the conservation of some species and there is no holistic approach for analysing the effects arising from OWF construction and operation. The objective of this article is to promote a sampling strategy to collect data on the different ecosystem compartments of the future Dieppe-Le Tréport (DLT) wind farm site, adopting an ecosystem approach, which could be applied to other OWFs for the implementation of a trophic network analysis. For that purpose, an Ecopath model is used here to derive indices from Ecological Network Analysis (ENA) to investigate the ecosystem structure and functioning. The results show that the ecosystem is most likely detritus-based, associated with a biomass dominated by bivalves, which could act as a dead end for a classic trophic food web since their consumption by top predators is low in comparison to their biomass. The systemic approach developed for DLT OWF site should be applied for other French and European installations of Offshore Wind Farm.

The invasive benthic foraminifera Trochammina hadai has been found for the first time in Europe along the coast of Normandy. Its native range of distribution is in Asia (Japan and Korea), and it has also been introduced along the coasts of western North America, Brazil and Australia. Morphological and molecular assessments confirm that specimens found in Le Havre and Caen-Ouistreham harbors belong to the Asiatic type. Like in Asia, T. hadai was found in transitional waters with muddy sediments. It exhibited high relative abundances (up to about 40%) confirming that T. hadai is a highly competitive species. In the present study, it was nearly absent from natural transitional waters and very abundant in heavily modified habitats like harbors, suggesting that ballast waters may likely be the vector of introduction. It was not recorded farther north along the coast of the Hauts-de-France. It is further hypothesized that the finding of a few specimens outside the harbor may facilitate the expansion of T. hadai in the English Channel by means of propagules dispersion.