Scientists at the University of Sydney have discovered that fish exposed to the industrial chemical BPA in warmer waters require more food to grow and reach a certain size.
The new study also indicates that fish exposed to higher temperatures and a common chemical found in plastics experience stunted growth. It shows that the combination of plastic pollution and global warming has significant negative impacts on marine populations. In environments containing the industrial chemical bisphenol A – commonly known as BPA – fish will need more energy to grow in warmer waters.
BPA is directly related to reproductive and developmental functions.
BPA is a widely used chemical in plastic production and has been shown to disrupt hormone signaling, affecting metabolic processes and growth in marine animals. In humans, BPA is directly linked to reproductive and developmental functions. Unfortunately, millions of tons of this compound continue to be produced globally each year.
The scientists conducted an experiment with zebrafish exposed to levels of BPA commonly found in waterways. They found that the chemical reduced the energy needed for fish to grow at 24 degrees Celsius, but when the water temperature reached 30 degrees Celsius, it significantly hindered their growth. The 30 degrees Celsius mark is a temperature that these species can frequently encounter in their natural habitats due to the effects of global warming.
This result underscores the necessity for intervention to mitigate climate change and plastic waste globally, said Frank Seebacher, a biology professor at the University of Sydney and author of the study. He added: “The combination of high temperatures and BPA increases the energy costs for growth, meaning that animals need to eat more to thrive and develop; this issue primarily affects larger fish species and predators.”
“In marine environments, there exists another layer of nutrition from smaller animals, but their numbers will decline due to plastic pollution and global warming. This poses a latent problem for sustainability in catch rates as fish stocks diminish.” BPA is released into marine environments from industrial wastewater, similar to the degradation of plastics. “Wherever there are many manufacturing plants and high plastic pollution, you will find elevated levels of BPA.”
Researchers have also attempted to model the risks of warming and plastic pollution in coastal areas combined with current fishing intensities. This analysis predicts that Southeast Asia is at the highest risk for reduced fish biomass directly affected by warming and pollution. Additionally, North and South America will also be significantly impacted.
A limitation of this finding is that the experimental subjects used by scientists were zebrafish, which are small freshwater fish. However, Seebacher hopes that these findings will also apply to other fish species, although more research is needed to confirm this.
He stated: “All endocrine systems are highly conserved among vertebrates, and there are still differences among vertebrates in how they respond to plastic pollution, but the ability to survive and grow in all species must be shown to be affected.”
