Microplastics (MPs) are small, plastic particles of various shapes, sizes and polymers.Although well studied in marine systems, their roles and importance in freshwater environments remain uncertain. Nevertheless, the restricted ranges and variable traits of freshwater fishes result in their communities being important receptors and strong bioindicators of MP pollution. Here, the current knowledge on MPs in freshwater fishes is synthesized, along with the development of recommendations for future research and sample processing. MPs are commonly ingested and passively taken up by numerous freshwater fishes, with ingestion patterns often related to individual traits (e.g. body size, trophic level) and environmental factors (e.g. local urbanization, habitat features). Controlled MP exposure studies highlight various effects on fish physiology, biochemistry and behaviour that are often complex, unpredictable, species-specific and nonlinear in respect of dose-response relationships.Egestion is typically rapid and effective, although particles of a particular shape and/ or size may remain, or translocate across the intestinal wall to other organs via the blood. Regarding future studies, there is a need to understand the interactions of MP pollution with other anthropogenic stressors (e.g. warming, eutrophication), with a concomitant requirement to increase the complexity of studies to enable impact assessment at population, community and ecosystem levels, and to determine whether there are consequences for processes, such as parasite transmission, where MPs could vector parasites or increase infection susceptibility. This knowledge will determine the extent to which MP pollution can be considered a major anthropogenic stressor of freshwaters in this era of global environmental change.

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High environmental microplastic pollution, and its largely unquantified impacts on organisms, are driving studies to assess their potential entry pathways into freshwaters. Recreational angling, where many anglers release manufactured baits into freshwater ecosystems, is a widespread activity with important socio-economic implications in Europe. It also represents a potential microplastic pathway into freshwaters that has yet to be quantified. Correspondingly, we analysed three different categories of industrially-produced baits (‘groundbait’, ‘boilies’ and ‘pellets’) for their microplastic contamination (particles 700 µm to 5 mm). From 160 samples, 28 microplastics were identified in groundbait and boilies, with a mean concentration of 17.4 (± 48.1 SD) MP kg−1 and 6.78 (± 29.8 SD) mg kg−1, yet no microplastics within this size range were recorded in the pellets. Microplastic concentrations significantly differed between bait categories and companies, but microplastic characteristics did not vary. There was no correlation between microplastic contamination and the number of bait ingredients, but it was positively correlated with C:N ratio, indicating a higher contamination in baits with higher proportion of plant-based ingredients. We thus reveal that bait microplastics introduced accidentally during manufacturing and/or those originating from contaminated raw ingredients might be transferred into freshwaters. However, further studies are needed to quantify the relative importance of this cryptic source of contamination and how it influences microplastic levels in wild fish.

Multiple demographic factors can affect ranger experiences and perceptions of their work, including factors like gender, age, and income. Similarly, whether a ranger is local to their conservation area might influence their experiences and perceptions of the work. This premise, however, has received limited attention. In this study we use survey data from across 11 countries to explore how being local to a conservation area might affect ranger experiences and perceptions. We define local rangers as originally being from within 20km of their conservation area. Our findings suggest that being local corresponds to more positive relations with local communities. Our results also imply that whilst being a local ranger might not directly affect job satisfaction, local rangers may well enjoy higher job satisfaction because of how they tend to differ from non-local rangers in other characteristics (e.g., lower formal education; greater access to familial support; more amicable community relations). Moreover, our findings indicate that non-local rangers tend to experience certain symptoms associated with a challenging job (e.g., feeling worn out and emotionally exhausted) more regularly than local rangers, which might correspond to lower welfare. In all, our findings indicate that further, more in-depth research into how the perceptions and experiences of local versus non-local rangers might differ could be useful. Examining the links between being a local ranger and community relations might be especially valuable.