Uptake, depuration, and behavioural effects of oxazepam on activity and foraging in a tropical snail (Melanoides tuberculata)

Pharmaceuticals are increasingly being detected in surface waters around the globe, giving rise to concerns that they may alter the physiology and behaviour of aquatic organisms exposed in the wild. Invertebrates represent important components of many ecosystems and bear a high potential for transmitting pharmaceutical contaminants to higher trophic levels. Here, we present a laboratory study in which we exposed a freshwater tropical snail, Melanoides tuberculata, to a serial dilution of the benzodiazepine oxazepam ranging from 50 ng/L to 5 mg/L. We tested for subsequent behavioural effects, including locomotor activity and foraging propensity, at two diurnal time points (day and night), and across three days. We found that the snails displayed a high level of behavioural tolerance to all treatments of oxazepam except at the highest exposure, where locomotor and foraging activity declined. We also detected a weak non-monotonic response curve suggestive of behavioural disinhibition at moderate exposure levels. Regardless of treatment, the snails were also less active after three days of exposure and more active during nighttime observations. We measured the uptake of oxazepam in tissues across treatments, showing that it bioconcentrated at up to 29 times the water exposure level (BCF range: 7 - 29). Finally, we characterized the uptake/depuration pharmacokinetics of oxazepam in snail tissues across time, which revealed that the snails reach a steady state equilibrium i

Ponds as experimental arenas for studying animal movement: current research and future prospects

Animal movement is a multifaceted process that occurs for multiple reasons with powerful consequences for food web and ecosystem dynamics. New paradigms and technical innovations have recently pervaded the field, providing increasingly powerful means to deliver fine-scale movement data, attracting renewed interest. Specifically in the aquatic environment, tracking with acoustic telemetry now provides integral spatiotemporal information to follow individual movements in the wild. Yet, this technology also holds great promise for experimental studies, enhancing our ability to truly establish cause-and-effect relationships. Here, we argue that ponds with well-defined borders (i.e. "islands in a sea of land") are particularly well suited for this purpose. To support our argument, we also discuss recent experiences from studies conducted in an innovative experimental infrastructure, composed of replicated ponds equipped with modern aquatic telemetry systems that allow for unparalleled insights into the movement patterns of individual animals

Cost-Effective Pharmaceutical Implants in Fish: Validating the Performance of Slow-Release Implants for the Antidepressant Fluoxetine

Internal, slow-release implants can be an effective way to manipulate animal physiology or deliver a chemical exposure over long periods of time without the need for an exogenous exposure route. Slow-release implants involve dissolving a compound in a lipid-based carrier, which is inserted into the body of an organism. However, the release kinetics of the compound from the implant to body tissues also requires careful validation. We tested and validated a slow-release implant methodology for exposing fish to a pharmaceutical pollutant, fluoxetine. We tested two lipid-based carriers (coconut oil or vegetable shortening) in the common roach (Rutilus rutilus). The implants contained either a high (50 mu g/g), low (25 mu g/g), or control (0 mu g/g) concentration of fluoxetine, and we measured tissue uptake in the brain, muscle, and plasma of implanted fish over 25 days. The two carriers released fluoxetine differently over time: coconut oil released fluoxetine in an accelerating manner (tissue uptake displayed a positive quadratic curvature), whereas vegetable shortening released fluoxetine in a decelerating manner (a negative quadratic curvature). For both carrier types, fluoxetine was measured at the highest concentration in the brain, followed by muscle and plasma. By comparing the implant exposures with waterborne exposures in the published literature, we showed that the implants delivered an internal exposure that would be similar if fish were exposed in surface waters containing effluents. Overall, we showed that slow-release internal implants are an effective method for delivering chronic exposures of fluoxetine over at least 1-month time scales. Internal exposures can be an especially powerful experimental tool when coupled with field-based study designs to assess the impacts of pharmaceutical pollutants in complex natural environments. Environ Toxicol Chem 2023;00:1-10. (c) 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC

Environmentally relevant concentration of caffeine-effect on activity and circadian rhythm in wild perch

We studied the ecological consequences of widespread caffeine contamination by conducting an experiment focused on changes in the behavioral traits of wild perch (Perca fluviatilis) after waterborne exposure to 10 mu g L-1 of caffeine. We monitored fish swimming performance during both light and dark conditions to study the effect of caffeine on fish activity and circadian rhythm, using a novel three-dimensional tracking system that enabled positioning even in complete darkness. All individuals underwent three behavioral trials-before exposure, after 24 h of exposure, and after 5 days of exposure. We did not observe any effect of the given caffeine concentration on fish activity under light or dark conditions. Regardless of caffeine exposure, fish swimming performance was significantly affected by both the light-dark conditions and repeating of behavioral trials. Individuals in both treatments swam significantly more during the light condition and their activity increased with time as follows: before exposure < after 24 h of exposure < after 5 days of exposure. We confirmed that the three-dimensional automated tracking system based on infrared sensors was highly effective for conducting behavioral experiments under completely dark conditions

Hur stor behöver en ettårig öring eller lax vara? : förslag till en strategi för att sortera ut ensomrig fisk på hösten som blir smolt till våren

Ett av de svåraste momenten inom kompensationsodling av lax och havsöring är att bedöma om fisken är tillräckligt stor för att utvecklas till ettårig smolt. Syftet med detta projekt var att testa en sorteringsstrategi för att förenkla denna bedömning för odlingspersonalen. Strategin gick ut på att ensomrig lax och öring på hösten delades upp i olika storleksklasser och under den kommande våren undersöktes deras prestanda som ettårig smolt i vandringsbassänger och i en bäck. På sensommaren eller hösten året innan odlad fisk ska vandra ut i havet startar den fysiologiska utvecklingen till smolt om fisken nått en viss kritisk storlek. Den exakta tidpunkten för när storleken ska ha uppnåtts är dock oklar vilket gör det svårt för personal på odlingarna att veta när fisken ska sorteras. Resultatet från detta projektvisade att en lax som är minst 10 cm lång i november med hög sannolikhet kommer att bli smolt till våren. Dessa laxar uppträdde i de flesta avseenden som en vandringsfärdig smolt följande vår och betedde sig mycket likt den tvååriga laxsmolten. Dock förekom det en storleksrelaterad predationsrisk i bäcken efter utsättning där ettårig lax drabbades i större utsträckning än tvåårig lax. Vi föreslår en strategi där laxen sorteras i tre storleksklasser i månadsskiftet augusti-september. Om någon av de tre storleksklasserna i medeltal ligger nära 10 cm i november föreslås en andra sortering för att plocka ut fisk större än 10 cm. All fisk mindre än 10 cm bör hållas kvar i odlingen och sättas ut som tvåårig smolt. För ettårig öring var resultaten mer komplexa. I vandringsbassängerna uppvisade fisk i storleksintervallet 10–16 cm ett beteende som indikerade att de var vandringsfärdiga smolt. Efter utsättningen i bäcken vandrade de dock mycket långsamt och predationen från i första hand skrattmås och fiskmås var hög, speciellt för de minsta öringarna. Jämfört med tvåårig öring var det få ettåriga individer som klarade att lämna bäcken efter utsättning. Om detta berodde på att de inte utvecklats till smolt eller om deras vandring i bäcken påverkades av predationsrisken i bäcken är oklart. Mer data behövs för att förstå den storleksrelaterade tröskeleffekten hos ettårig öring innan förslag på sorteringsrutiner kan ges. Vi föreslår att utsättningen av speciellt öring men också lax bör ske i en miljö med stort vattendjup och högt flöde för att minimera predationsrisken från i första hand fåglar

Predicting the impacts of chemical pollutants on animal groups

Wildlife are exposed to an increasing number and diversity of chemical pollutants.Chemical pollutants can elicit a range of sublethal effects on individual organisms, but research on how these contaminants affect social interactions and animal groups is severely lacking.It is imperative that perspectives from behavioural ecology and ecotoxicology are integrated, to increase our understanding of how contaminant effects on individuals might cascade to group-level processes.We present a conceptual framework for researchers and practitioners to guide the study of how chemical pollutants might affect the emergence, organisation, and function of animal social groups.Chemical pollution is among the fastest-growing agents of global change. Synthetic chemicals with diverse modes-of-action are being detected in the tissues of wildlife and pervade entire food webs. Although such pollutants can elicit a range of sublethal effects on individual organisms, research on how chemical pollutants affect animal groups is severely lacking. Here we synthesise research from two related, but largely segregated fields – ecotoxicology and behavioural ecology – to examine pathways by which chemical contaminants could disrupt processes that govern the emergence, self-organisation, and collective function of animal groups. Our review provides a roadmap for prioritising the study of chemical pollutants within the context of sociality and highlights important methodological advancements for future research

Emerging investigator series: : Use of behavioural endpoints in regulation of chemicals

Interest in behavioural ecotoxicology is growing, partly due to technological and computational advances in recording behaviours but also because of improvements of detection capacity facilitating reporting effects at environmentally relevant concentrations. The peer-reviewed literature now contains studies investigating the effects of chemicals, including pesticides and pharmaceuticals, on migration, dispersal, aggression, sociabilitygrouping, reproduction, feeding and anti-predator behaviours in vertebrates and invertebrates. To understand how behavioural studies could be used in regulatory decision-making we: 1) assessed the legal obstacles to using behavioural endpoints in EU chemicals regulation; 2) analysed the known cases of use of behavioural endpoints in EU chemicals regulation; and 3) provided examples of behavioural endpoints of relevance for population level effects. We conclude that the only legal obstacle to the use of behavioural endpoints in EU chemicals regulation is whether an endpoint is considered to be relevant at the population level or not. We also conclude that ecotoxicity studies investigating behavioural endpoints are occasionally used in the EU chemicals regulation, and underscore that behavioural endpoints can be relevant at the population level. To improve the current use of behavioural studies in regulatory decision-making contribution from all relevant stakeholders is required. We have the following recommendations: 1) researchers should conduct robust, well-designed and transparent studies that emphasize the relevance of the study for regulation of chemicals; 2) editors and scientific journals should promote detailed, reliable and clearly reported studies; 3) regulatory agencies and the chemical industry need to embrace new behavioural endpoints of relevance at the population level

Pharmaceutical pollution disrupts the behaviour and predator–prey interactions of two widespread aquatic insects

Pharmaceutical pollution represents a rapidly growing threat to ecosystems worldwide. Drugs are now commonly detected in the tissues of wildlife and have the potential to alter the natural expression of behavior, though relatively little is known about how pharmaceuticals impact predator-prey interactions. We conducted parallel laboratory experiments using larval odonates (dragonfly and damselfly nymphs) to investigate the effects of exposure to two pharmaceuticals, cetirizine and citalopram, and their mixture on the outcomes of predator-prey interactions. We found that exposure to both compounds elevated dragonfly activity and impacted their predation success and efficiency in complex ways. While exposure to citalopram reduced predation efficiency, exposure to cetirizine showed varied effects, with predation success being enhanced in some contexts but impaired in others. Our findings underscore the importance of evaluating pharmaceutical effects under multiple contexts and indicate that these compounds can affect predator-prey outcomes at sublethal concentrations