%0 Newspaper Article %B Aquatic Invasions %D 2020 %T Establishment and population features of the non-native Atlantic rangia, Rangia cuneata (Mollusca: Bivalvia), in northwestern France %A Robin Faillettaz %A Christophe Roger %A Michel Mathieu %A Jean-Paul Robin %A Katherine Costil %K Alien species %K brackish waters %K density %K Growth %K Normandy (F) %K Reproduction %K The Atlantic rangia %X The presence of shells of the Atlantic rangia, Rangia cuneata, a brackish-water species native from the Gulf of Mexico also known as gulf wedge clam, was reported in 2017 on the French coasts of the English Channel, in the waterway that connects Caen to the sea. However, no information was available on whether a population of this alien species had successfully established in the region. Here, only empty shells—except for one live individual—were sampled in that waterway, and the sampling was shifted to the nearby marina of Ouistreham, where water is mesohaline (6.89 ± SD 0.06 PSU). In spring 2017, the mean density in the marina reached 110.45 ± 86.08 ind m-2, largely dominating the benthos community. The population was mostly composed of fairly large individuals, with no young-of-the-year found inside the marina. The modal values of the size frequency distribution ranged between 35 and 40 mm shell length. The growth patterns determined from the annual rings suggest a maximum lifespan of eight completed years. Following the assumption that colonization occurred at the larval stage, as in other European countries, this population may have established in 2009, i.e. only four years after its first detection in Europe, in the Antwerp harbour. The specimens collected are the largest recorded in European waters, suggesting that a highly suitable environment for the species in the region. Given the invasive potential of Atlantic rangia within the last decade, a close monitoring of this population and of the spread of the species in French and European waters appears necessary to determine its impacts on these ecosystems. %B Aquatic Invasions %V 15 %P 367-381 %G eng %0 Journal Article %J Estuarine, Coastal and Shelf Science %D 2018 %T Distribution, associated species and extent of biofouling “reefs” formed by the alien species Ficopomatus enigmaticus (Annelida, Polychaeta) in marinas %A Maud Charles %A Robin Faillettaz %A Nicolas Desroy %A Jérôme Fournier %A Katherine Costil %K Alien species %K Benthic communities %K Biofouling %K Ficopomatus enigmaticus %K Marinas %K Normandy %X

Artificial structures in ports are commonly colonized by non-indigenous epifauna that tolerate high pollution levels. Bioconstructions built by alien species may offer sheltered microhabitats for motile (vagile) animals but biofouling often becomes detrimental to human activities. In this context, the present study provides an inventory of 1) the extent of biofouling related to the alien Polychaeta Ficopomatus enigmaticus on hard structures of marinas in Normandy, France, and 2) the biodiversity of sessile (attached) or vagile (motile) fauna associated with these “reefs”, including both native and alien species. Reefs built by F. enigmaticus were found in 6 out of 12 marinas with oligohaline-mesohaline waters. Significant differences in the total volume of biofouling were found among sites, with maximum values observed in Honfleur's old basin (459.52 mL per 0.04 m2). Ficopomatus enigmaticus greatly dominated the sessile invertebrate community both in volume (74–100%) and weight (70–100%) in 5 out of 6 marinas. The fouling formed by 5 alien species was colonized by 15 motile invertebrate taxa, including 3 cryptogenic or alien species. The alien crab Rhithropanopeus harrisi displayed the highest frequency of occurrence (>80%) and mean density (>300 ind m−2), and the global densities of sessile (except F. enigmaticus) and motile fauna were significantly correlated (r = 0.824; p < 0.05). While motile fauna density was also significantly correlated with the biovolume of B. improvisus and M. leucophaeata, it was not with F. enigmaticus (r = 0.421; p > 0.05). In line with previous studies, these results suggest that F. enigmaticus acts as an engineer offering shelter for reef-associated organisms. In addition, results suggest that at the regional scale, inter-site differences in motile fauna may reflect differences in environmental parameters such as salinity. The presence of F. enigmaticus at low salinity levels led to assess its potential distribution at the scale of the European coasts, suggesting that in the context of climate change, favorable conditions for spawning (>18 °C) will likely expand towards the North, and particularly in the eastern and northern Baltic Sea.

%B Estuarine, Coastal and Shelf Science %G eng %R https://doi.org/10.1016/j.ecss.2018.07.007