Researchers stunned by behavior shift in unique fish species: 'Need for more comprehensive research'

Common pollutants have a significant impact on fish activity, a new study has found.

What's happening?

Researchers from Sultan Qaboos University in Oman studied the effects of common pollutants — chemicals, noise, and light — on zebrafish. Their findings were published in the April edition of Science of the Total Environment.

The fish were exposed to various levels of fluoxetine (often sold under the brand name Prozac) along with artificial light at night and simulated motorboat noises. These were chosen to simulate common stressors that fish deal with, especially when living in urban environments.

Those exposed to fluoxetine were less bold, while those exposed to nighttime light pollution were bolder and more active. Motorboat noises also tended to make the fish more active.

Perhaps most interesting is how the factors at play seemed to interact to produce different results in the fish. Fluoxetine exposure seemed to reduce the activity typically seen as a consequence of noise and light pollution. And the effects of the motorboat noises on the fish depended heavily on when the animals were exposed to the sounds.

"Fish that were tested with noise first often reacted more strongly than those that were initially tested without noise, suggesting that noise increased the stress of adaption to a new environment," the study's co-authors wrote.

Why is this important?

The authors believe this is the first study to determine how chemical, noise, and light pollution can interact to affect fish, which is important because it's rare that pollution is isolated in the real world.

Previous studies have shown that low amounts of fluoxetine could threaten fish, as it "reduced the body condition and sperm vitality of male guppies over multiple generations," according to The Guardian. It's not uncommon for fluoxetine — and other chemicals — to enter waterways when people flush pharmaceuticals down the toilet, so studying the drug's potential effects on marine life makes sense.

A number of studies have also shown how the light and noise created by human activity can wreak havoc on wildlife. One study found that hundreds of mammal species no longer follow their normal activity patterns and have drastically changed their daily schedules due to human disruptions.

What can be done about this?

This new study points to the dangers that urban sprawl can pose to wildlife. It also emphasizes the importance of continuing to explore how several factors, which may typically be studied individually, might overlap to impact an ecosystem.

Do you worry about air pollution in your town? All the time 💯 Often 😢 Only sometimes 😟 Never 😎 Click your choice to see results and speak your mind.

"Environmental stressors often co-exist in the real world and the limited number of studies in this area underscores the need for more comprehensive research," the paper's co-authors wrote.

Learning more about the potential for human activity to influence animals could help inform policies and decision-making that shape where and how we live.

Join our free newsletter for good news and useful tips, and don't miss this cool list of easy ways to help yourself while helping the planet.