Natural daily patterns in fish behaviour may confound results of ecotoxicological testing. (1st May 2021)

• Record Type: Journal Article
• Authors: Thoré, Eli S.J.; Brendonck, Luc; Pinceel, Tom
• Is Part Of: Environmental pollution. Volume 276(2021)
• Publication Date: 2021-05-01
• Subjects: Biological rhythm -- Circadian rhythmicity -- Fish -- Neuroactive -- Pollution; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.116738
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Low doses of neuroactive chemicals end up in the environment and disrupt behaviour of non-target organisms. Although a whole range of studies have documented pollutant-induced changes in behaviour, natural daily variability in behaviour is rarely taken into account. This is surprising because biological rhythms may affect the outcome of experiments, are adaptive and are expected to be sensitive to neurochemical exposure. Here, we exploit daily behavioural variation in the fish model Nothobranchius furzeri to examine if behavioural effects of chronic exposure (74 days) to an environmentally relevant level (28 ng/L) of the neurochemical fluoxetine depend on the time of day. Fluoxetine exposure induced an increase in anxiety-related behaviour that was slightly more pronounced in the evening compared to the morning. Moreover, open-field locomotor activity was disrupted and daily patterns in activity lifted upon exposure to the compound. These results imply that short-term behavioural variability should be considered both to standardise ecological risk assessment of neuroactive chemicals as well as to better understand the environmental impact of such compounds in aquatic ecosystems. Graphical abstract: Image 1 Highlights: Ecotoxicology rarely considers natural daily variability in behaviour. We study fluoxetine impact on turquoise killifish in the morning vs. evening. Fluoxetine induces more anxiety in the evening than in the morning. Fluoxetine decreases activity and lifts daily activity patterns. Natural biological rhythms may confound, and be sensitive to, chemical impact. Abstract : Main finding: Fluoxetine lifts daily activity patterns and increases anxiety-like behaviour to a degree that depends on the time of day.