The psychoactive pollutant fluoxetine compromises antipredator behaviour in fish

Area of Science:

• Environmental Science
• Ecotoxicology
• Behavioral Ecology

Background:

• Pharmaceuticals, including antidepressants like fluoxetine, are emerging contaminants in aquatic environments.
• These pollutants pose risks to wildlife, impacting behavior even at low concentrations.
• Limited research exists on fluoxetine's behavioral effects at ecologically relevant levels.

Purpose of the Study:

• To investigate the behavioral impacts of fluoxetine exposure on Eastern mosquitofish (Gambusia holbrooki) at environmentally realistic concentrations.
• To determine if fluoxetine alters antipredator behavior and activity levels in fish.

Main Methods:

• Mosquitofish were exposed to fluoxetine for 28 days at two ecologically relevant concentrations.
• Antipredator behaviors, including activity levels and freezing responses, were assessed in the presence and absence of predators.
• Behavioral changes were analyzed in relation to exposure concentration and sex.

Main Results:

• Low-dose fluoxetine exposure increased mosquitofish activity, regardless of predator presence.
• Fluoxetine-exposed fish entered the predator 'strike zone' faster at both concentrations.
• Freezing behavior was reduced post-simulated strike, with a sex-dependent effect observed at lower doses.

Conclusions:

• Fluoxetine exposure at environmentally realistic concentrations alters critical antipredator behaviors in mosquitofish.
• Findings indicate non-monotonic and sex-dependent behavioral shifts.
• Altered behaviors have significant implications for individual fitness and survival in contaminated aquatic ecosystems.