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The signal crayfish Pacifastacus leniusculus is one of the most widespread non-indigenous crayfish in Europe and is of interest to aquaculture in many countries. Once they escape into the wild, they disperse and become a potential source of food exploited for consumption by local inhabitants. The ingestion of plastics by the invasive signal crayfish in the Wieprza River, a tributary to the Baltic Sea, was determined by the FTIR identification of plastic compounds found in stomachs. The occurrence of plastic debris in the stomachs of P. leniusculus is reported for the first time. Plastic particles with the size range between 70 and 450 µm were observed only among crayfish inhabiting the lower, urbanized part of the river (7.3% of specimens). The presence of PTFE (polytetrafluoroethylene), cellophane, PP (polypropylene), PE (polyethylene), PMMA (polymethyl methacrylate), and nylon was confirmed with the highest frequency of PTFE in the stomachs of crayfish. Fibres were the predominant type of microplastics in crayfish stomachs. The results indicated the size-selective uptake and ingestion of plastics depending on the traits of the species and environment. [ABSTRACT FROM AUTHOR]

Aim: Invasive alien species are a growing problem worldwide due to their ecological, economic and human health impacts. The "killer shrimp" Dikerogammarus villosus is a notorious invasive alien amphipod from the Ponto‐Caspian region that has invaded many fresh and brackish waters across Europe. Understandings of large‐scale population dynamics of highly impactful invaders such as D. villosus are lacking, inhibiting predictions of impact and efficient timing of management strategies. Hence, our aim was to assess trends and dynamics of D. villosus as well as its impacts in freshwater rivers and streams. Location: Europe. Methods: We analysed 96 European time series between 1994 and 2019 and identified trends in the relative abundance (i.e. dominance %) of D. villosus in invaded time series, as well as a set of site‐specific characteristics to identify drivers and determinants of population changes and invasion dynamics using meta‐regression modelling. We also looked at the spread over space and time to estimate the invasion speed (km/year) of D. villosus in Europe. We investigated the impact of D. villosus abundance on recipient community metrics (i.e. abundance, taxa richness, temporal turnover, Shannon diversity and Pielou evenness) using generalized linear models. Results: Population trends varied across the time series. Nevertheless, community dominance of D. villosus increased over time across all time series. The frequency of occurrences (used as a proxy for invader spread) was well described by a Pareto distribution, whereby we estimated a lag phase (i.e. the time between introduction and spatial expansion) of approximately 28 years, followed by a gradual increase before new occurrences declined rapidly in the long term. D. villosus population change was associated with decreased taxa richness, community turnover and Shannon diversity. Main Conclusion: Our results show that D. villosus is well‐established in European waters and its abundance significantly alters ecological communities. However, the multidecadal lag phase prior to observed spatial expansion suggests that initial introductions by D. villosus are cryptic, thus signalling the need for more effective early detection methods. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA), an endocrine-disrupting chemical (EDC), has strong potential for daily exposure to humans and animals due to its persistence and widespread in the environment, so its effects directly concern public health. Although invertebrates represent important components of aquatic ecosystems and are at significant risk of exposure, there is little information about the biological effects of EDCs in these organisms. Astacus leptodactylus used in this study is one of the most consumed and exported freshwater species in Europe. In this study, the 96-h effect of BPA on A. leptodactylus was examined using various biomarkers. The LC50 value of BPA was determined as 96.45 mg L−1. After 96 h of exposure to BPA, there were increases in superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activities and levels of malondialdehyde (MDA), and total oxidant status context (TOSC), and there were decreases in the activity of glutathione reductase (GR), carboxylesterase (CaE), acetylcholinesterase (AChE), Na+/K+ ATPase, Mg2+ ATPase, Ca2+ ATPase, and total ATPase and the total antioxidant context (TAC). From the results of this study, it can be concluded that BPA has significant toxic effects on A. leptodactylus based on the selected biochemical parameters of antioxidant, cholinergic, detoxification, and metabolic systems in crayfish even at low doses. Thus, it can be said that BPA can seriously threaten the aquatic ecosystem and public health. [ABSTRACT FROM AUTHOR]

The triazine herbicide atrazine is routinely detected in freshwaters, and has also been detected in coastal waters in Europe and the US. Relatively few atrazine studies have been conducted with estuarine/marine invertebrates. This study sought to contribute additional invertebrate atrazine toxicity data using model species, Eastern oyster (Crassostrea virginica) and Mysid shrimp (Americamysis bahia). Specifically, we investigated (1) acute effects on survival and growth of Eastern oyster, and (2) acute and chronic effects on survival, reproduction, and growth of the Mysid shrimp. No oyster mortality was observed following 96-h exposure to up to 17 mg a.i./L, but shell growth was reduced by 0.55% to 16% in 1.0, 9.2, and 17 mg a.i./L treatments, resulting in a 96-h EC50 of > 17 mg a.i./L. In the 96-h Mysid test, mortality rates of 5 to 70% were observed in 1.7, 2.4, 3.6, and 6.4 mg a.i./L treatments, and the 96-h LC50 was 5.4 mg a.i./L. Sub-lethal effects were observed among surviving Mysids exposed to ≥ 2.4 mg a.i./L. After 28 days of exposure to up to 1.1 mg a.i./L, there were no effects on survival or reproduction. The LOEC was 0.50 mg a.i./L, based on reduced body size, and the NOEC was 0.26 mg a.i./L. Overall, the results indicate that atrazine is slightly toxic towards Eastern oyster and moderately toxic to the Mysid shrimp under acute exposure conditions. These data will help to fill a gap in the literature and inform risk assessment of potential effects of atrazine towards estuarine/marine communities. [ABSTRACT FROM AUTHOR]

Abstract Increasing production of energy crops in Europe, mainly maize and rapeseed, has altered patterns of pesticide use in recent decades. The long-term effects of S-metolachlor (S-M) and of its metabolite metolachlor OA (M-OA) at the environmentally relevant concentration of 4.2 μg L−1 and at 42 μg L−1 (ten-fold concentration) on marbled crayfish (Procambarus virginalis) were evaluated in a 28-day exposure and after a subsequent 28-day recovery period. Indicators assessed were behaviour; biochemical haemolymph profile; oxidative and antioxidant parameters of gill, hepatopancreas, and muscle; and histology of hepatopancreas and gill. Results showed biochemical haemolymph profile (lactate, alanine aminotransferase, aspartate aminotransferase, inorganic phosphate), lipid peroxidation in hepatopancreas, and antioxidant parameters (catalase, reduced glutathione, glutathione S-transferase) of hepatopancreas and gill of crayfish exposed to S-M and M-OA to significantly differ from controls (P < 0.01). Antioxidant biomarker levels remained different from controls after a 28-day recovery period. Differences in behaviour including speed of movement and velocity, and histopathological damage to gill and hepatopancreas were associated with S-M and M-OA exposure and persisted after 28 days in S-M- and M-OA-free water. Results suggest harmful effects of low concentrations of S-M and its metabolite M-OA on non-target organisms and provide information for assessing their effects at environmentally relevant concentrations. Highlights • S-metolachlor and its metabolite metolachlor OA are frequently detected in rivers. • Their harmful effects were studied on the non-target invertebrate at an environmentally relevant concentration. • Exposure to these compounds was associated with changes in biochemical parameters, histology, and behaviour in crayfish. • Damage was not reversed by 28 days recovery in clean water. [ABSTRACT FROM AUTHOR]

Abstract: We describe a microsporidian parasite infecting non-native Chinese mitten crabs (Eriochier sinensis) from Europe. Electron microscopy revealed merogonic and sporogonic life stages bound within a plasmalemma. The crab parasite develops polar tube precursors at the sporont stage but does not complete formation of the intact spore extrusion apparatus at the stage of the sporogonial plasmodium like Enterocytozoon bienuesi and other representatives of the Enterocytozoonidae. Its presence within an aquatic crustacean host, and a distinct molecular phylogeny based on partial small subunit ribosomal RNA (SSU rRNA) gene sequences also place it relatively close, though distinct to, existing genera within the Enterocytozoonidae. Consideration of morphological and phylogenetic characteristics of other hepatopancreas-infecting microsporidia from crustaceans suggests that certain ones (e.g. Enterospora canceri) are retained within the clade corresponding to the existing family Enterocytozoonidae, while others, including the parasite described here, may eventually be grouped in a sister taxon potentially of family rank. Based upon morphological and host similarity, it is likely that the parasite described here is the same as Endoreticulatus eriocheir (), previously described from Chinese mitten crabs in Asia. However, using a combined taxonomic approach based upon morphological and phylogenetic data, we propose the formation of a new genus (Hepatospora) to replace the previous generic classification of the Asian parasite as Endoreticulatus. The microsporidian from the hepatopancreas of E. sinensis is named Hepatospora eriocheir () gen. et comb. nov. It is assumed that the parasite was introduced during initial invasions of this crab to Europe during the early 20th Century. [Copyright &y& Elsevier]

The Chinese mitten crab, Eriocheir sinensis (H. Milne Edwards), is an invasive species that lives as an adult predominantly in freshwater but migrates seawards to breed. It has spread via ballast water and/or intentional introduction to Continental Europe, Southern France, U.S.A. (San Francisco Bay) and the United Kingdom. Analysis of detailed historic data from the outbreak in Europe was digitised and analysed using Geographical Information Software. This revealed that there were two separate invasions in Northern Europe and Southern France, with an average range expansion during the peak period of 562 km/year from 1928–1938 (Northern Europe) and 380 km/year from 1954–1960 in Southern France. Size class distribution data from the lower estuary of the River Elbe (Germany) (1932–1936) illustrate migration patterns to and from the estuary over the year. Marking experiments determined that the mean rate of downstream migration for adults was 11.5 km/day (SD 3.54; n=7), up to a maximum of 18.1 km/day. The carapace width of upstream-migrating animals increased by 3 mm/100 km. The peak period for upstream migration was March to July, followed by the downstream season from July to September. This data set, extracted from historic references, represents one of the most complete pictures of the life cycle and spreading behaviour of this alien invader. [ABSTRACT FROM AUTHOR]

Sediments and marine organisms such as mussels (Mytilus galloprovincialis), fish (Mullus barbatus, Serranus scriba), crabs (Polybius henslowi) and shrimp-like crustaceans (mysids, euphausiids) were sampled on European coasts, France, Spain) and analysed for their PAH contentby gas chromatography/mass spectrometry (GC-MS). The PAH concentrations determined in the organisms were significantly negatively correlated with logKow values, but to different extents accordingto the species. This was explained by the greater exposure of the organisms to the lower molecular weight compounds with differences resulting from different feeding habits, habitat, and biotransformation capacities of the organisms in relation to trophic levels. The influence of these observations on the use of different sentinel species in biomonitoring programmes is discussed. [ABSTRACT FROM AUTHOR]