Mass mortality events (MMEs) are decimating populations and compromising key ecosystem functions around the globe. One taxon particularly vulnerable to MMEs is freshwater bivalve mollusks. This group has important ecosystem engineering capacities and includes highly threatened and highly invasive taxa. Thus, MMEs of freshwater bivalves have important implications for conservation and ecosystems. Despite this, little is known a...

Behavioral endpoints have been increasingly used in ecotoxicology for their relevance to individual fitness and ecological effects. However, due to the lack of standard experimental protocols, behavioral endpoints are mostly excluded when deriving environmental quality guidelines. To increase reliability and comparability, behavioral endpoints need to be developed alongside standard endpoints in experiments incorporating eleme...

Freshwater bivalves are globally distributed, diverse, and common in benthic communities. Many taxa, particularly in the most species‐rich order, Unionida, are declining due to anthropogenic stressors, while a small number of non‐native species have become increasingly abundant and widespread, commonly replacing native bivalve assemblages. To understand how these global changes may impact ecosystems and people, we conducted a...

Studies on lakes as modifiers of manganese fluxes in pristine catchments are limited, despite manganese being a sensitive redox-change indicator and participating in the cycling of many key elements. We compiled 26 years of monitoring data from interconnected monomictic humic lake and dimictic clear-water lake to estimate the mean daily lakes' imports, pools and exports of manganese. The humic lake, surrounded by peatlands, ex...

The Enemy Release Hypothesis (ERH) proposes that the success of bioinvasions is attributable to lower enemy pressure on invasive species compared to native ones, giving a competitive advantage for invaders. In line with the hypothesis, we previously observed in northern European bodies of fresh water that invasive bivalves were subject to lower parasite pressure than sympatric native mussels. Here, we investigated ERH in three...

Sulfate is increasingly found in elevated concentrations in freshwater ecosystems due to anthropogenic activities. Chronic exposure to sulfate has been reported to cause sublethal effects on freshwater invertebrates. Previous sulfate toxicity tests have mostly been conducted in hard or moderately hard waters, and research on species inhabiting soft water is needed, given that freshwater organisms face heightened sensitivity to...

Anodonta anatina , a widely distributed Eurasian freshwater mussel, has dramatically declined and listed as endangered species in IUCN Red List in some parts of the Europe. To better understand its basic biology and possible sex-dependent effects of parasitism on reproduction, we investigated the reproductive traits, trematode parasitism and growth between November 2020 and October 2021. Our data from a Finnish population indi...

Chemical preservatives can alter stable isotope ratios in animal tissues. The effects of preservation on δ 13 C and δ 15 N values have been investigated in a variety of species, but not on δ 2 H values or on the freshwater pearl mussel (FPM, Margaritifera margaritifera ) tissues. We evaluated the effect of ethanol preservation (unpreserved vs preserved tissues) over 6 months on the δ 13 C, δ 15 N and δ 2 H values of FPM foot a...

Global decline of freshwater mussels (Unionoida) is threatening biodiversity and the essential ecosystem services that mussels provide. As filter-feeding organisms, freshwater mussels remove phytoplankton and suspended particles from the water. By filtering bacteria, freshwater mussels also decrease pathogen loads in the water. The objective of this study was to evaluate whether the common freshwater bivalve Anodonta anatina (...

An increasing threat to local, native freshwater mussels (Unionida)—an ecologically important but globally alarmingly declining group—is the invasion by exotic bivalves. The Enemy Release Hypothesis predicts that introduced species should benefit from enemy-mediated competition because they are less likely to be harmed by natural enemies, such as parasites, than their native competitors. We investigated within-site differences...

Conservation of the endangered freshwater pearl mussel (FPM) includes artificially rearing juveniles, but the pulsed flow-through (PFT) method, enabling the continuous renewal of water and food in culture containers, has not been applied to FPM. This study tested the PFT method in culture of FPM juveniles, and the effect of water source (tap vs well water) and food concentration (mixture of commercial phytoplankton products) o...

Effect of freshwater mussels’ (Unionoida) glochidia on the growth of fish host has remained poorly studied. We compared the specific growth rate of the juvenile, PIT-marked brown trout ( Salmo trutta ) between uninfected controls to those experimentally infected (average initial intensity of infection 8000 fish −1 ) with Margaritifera margaritifera glochidia, kept in high and low feeding. Growth and mortality of fish were moni...

Juveniles of the endangered freshwater pearl mussel (FPM, Margaritifera margaritifera ) live burrowed in stream substrate for the first years of their life. Fine sediments block water exchange within substrate and may cause juvenile mortality and recruitment failure. To better understand the connection between success of juvenile FPM and substrate particle size, it would be important to understand behavioural responses of FPM...