Fluoxetine enhances reproductive output without affecting spawning-site selection in turquoise killifish

Area of Science:

• Environmental Science
• Ecotoxicology
• Aquatic Ecology

Background:

• Pharmaceuticals, including antidepressants like fluoxetine, are common aquatic contaminants.
• Evidence suggests fluoxetine can increase fish offspring production, but potential impacts on reproductive behaviors are unclear.

Purpose of the Study:

• To investigate if environmentally relevant fluoxetine concentrations affect spawning site selection in turquoise killifish.
• To determine if fluoxetine alters reproductive output independently of habitat preference.

Main Methods:

• Turquoise killifish were exposed to a field-realistic concentration of fluoxetine (317 ng/L) in a controlled laboratory setting.
• Fish spawning preferences were assessed using substrates of varying colors (white, orange, black) in both single-pair and group settings.
• Habitat preference was also evaluated in a non-mating context over different colored backgrounds.

Main Results:

• Fluoxetine-exposed fish produced approximately 50% more eggs in single pairs, but this effect was not observed in group settings.
• Fish consistently preferred spawning on black sand over orange or white sand, regardless of fluoxetine exposure or social context.
• Fluoxetine did not alter spawning site preference or general habitat preference in non-mating contexts.

Conclusions:

• Environmentally relevant fluoxetine concentrations can enhance fish reproductive output without disrupting crucial spawning site selection behaviors.
• The ecological consequences of fluoxetine-induced reproductive changes depend on interactions with natural social and habitat dynamics.
• Further research is needed to understand the long-term implications of pharmaceutical pollution on fish populations and aquatic ecosystems.