Antidepressants in waterways disturb fish behaviour, study finds

mosquito fish

A new study led by Monash biologists has found that male fish exposed to the antidepressant fluoxetine (commonly marketed as ProzacTM) are spending more time pursuing female fish for sex.

The recently released study, published in Science of the Total Environment, is one of many recent findings delivered by Monash scientists examining effects of pharmaceutical pollutants in aquatic habitats.

A widespread contaminant of particular concern is the antidepressant fluoxetine, which can affect behavioural and physiological processes in non-target species.

“Despite this, the effects of fluoxetine on wildlife behaviour have seldom been investigated across multiple fitness-related contexts, especially at environmentally realistic concentrations,” said lead study author Jake Martin, a PhD candidate in the Behavioural Ecology Research Group at Monash University.

The researchers examined the impact of a 35 day fluoxetine exposure at two environmentally relevant concentrations (31 and 374 ng/L) across a suite of fitness-related contexts in wild-caught male mosquitofish.

“We investigated anxiety-related behaviours (boldness, exploration, and activity) and found no significant impacts of exposure,” Jake said.

“We then tested effects of fluoxetine in a reproductive context, including mating behaviour and sperm quality.”

The researchers found that fluoxetine exposure resulted in males spending a greater amount of time pursuing females, and that low-exposed males were more likely to attempt copulation than unexposed males.

“Our findings provide clear evidence that fluoxetine can produce context-specific behavioural effects in fish and underscore how pharmaceutical exposure at field-detected concentrations can induce important shifts in wildlife behaviour,” said study co-author Associate Professor Bob Wong, who leads the Behavioural Ecology Research Group in the School of Biological Sciences at Monash.

The research follows another landmark study from the Research Group, which found that   fluoxetine altered mechanisms of both pre- and post-copulatory sexual selection in mosquitofish. This study, led by PhD candidate Michael Bertram and published in Environmental Pollution, highlighted the capacity of pharmaceutical pollution to interfere with sensitive reproductive processes in wildlife, including sperm traits.

And in a third study published in Environmental Pollution, researchers from Bob Wong’s group found that fluoxetine can also affect behaviours needed to evade predators.


The full article by Jake Martin in the Science of the Total Environment is available here.

The full article by Michael Bertram in Environmental Pollution is available here.

The full second article by Jake Martin is in Environmental Pollution is available here.

For further information, or to arrange an interview with Jake Martin, Michael Bertram, or Associate Professor Bob Wong, please contact:

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