Effects of dispersant treated oil upon exploratory behaviour in juvenile European sea bass (Dicentrarchus labrax)

• Published in: Ecotoxicology and environmental safety 2021-01, Vol.208, p.111592, Article 111592
• Main Authors: Aimon, Cassandre, Lebigre, Christophe, Le Bayon, Nicolas, Le Floch, Stéphane, Claireaux, Guy
• Format: Article
• Language: English
• Subjects: Animals; Bass - physiology; Behaviour; Biodiversity and Ecology; Ecosystem; Environmental Sciences; European sea bass; Exploration; Exploratory Behavior; Hydrocarbons; Oil spill; Open field test; Petroleum; Petroleum Pollution; Teleost fish; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2020.111592

Accidental spills are pervasive pollution in aquatic ecosystems. Resorting to chemical dispersant is one of the most implemented strategies in response to oil spills, but it results in an increase in the bio-availability of oil compounds known to disturb fish neurosensory capacities and hence fish habitat use. While it has become well established that acute oil exposure can cause a range of physiological defects, sub-lethal consequences on animal behaviour have only received recent attention. Here we investigated the effect of an exposure to a 62 h- dispersant treated oil on the exploration tendency (exploratory activity, and avoidance of unfamiliar open areas) of juvenile European sea bass. Three different concentrations of chemically dispersed oil were tested, low and medium conditions bracketing the range of likely situations that fish encounter following an oil spill, the high dose representing a more severe condition. Fish recovery capacities were also evaluated during 2 weeks post-exposure. Our results suggest a dose-response relationship; the low dose (0.048 ± 0.007 g L-1 of total petroleum hydrocarbons ([TPH])) had no effect on sea bass behavioural response to a novel environment while medium (0.243 ± 0.012 g L-1 [TPH]) and high (0.902 ± 0.031 g L-1 [TPH]) doses altered fish exploratory activity and their typical avoidance of unfamiliar open areas. Our experiment also suggest signs of recovery capacities in the first 10 days following oil exposure even if fish might need more time to fully recover from observed alterations. We discuss the possibility that observed alterations may result from a neurosensory or physiological known defects of oil exposure, causing anaesthetic-like sedative behaviours. Altogether, this study shows that juvenile sea bass exposed to oil spill exhibit transient behavioural impairments that may have major population-level consequences given the high mortality experienced by juveniles. [Display omitted] •Dispersant treated oil exposure affected fish behaviour in a dose-dependent way.•Only the lowest concentration tested did not alter sea bass behaviour.•Fish exposed to high and medium conditions had altered exploratory activity.•Fish spent more time in the central and riskier area of the open field test.•Recovery was observed within 10 days when returned to clean unpolluted seawater.