The world's oceans are becoming so polluted that fish are losing their natural instinct to survive, according to new research published in the journal Nature Climate Change.
The study focused on fish that live in the coral reefs off the coast of Papua New Guinea, AFP reported. Not only were the fish losing their survival instinct, but they also showed signs of being attracted to the smell of predators.
"Fish will normally avoid the smell of a predator, that makes perfect sense," Philip Munday, a professor at James Cook University in Australia and the study's lead author, told AFP.
"But they start to become attracted to the smell of a predator. That's incredible.
"They also swim further from shelter and they are more active, they swim around more. That's riskier behavior for them- they are more likely to be attacked by a predator," Munday told AFP.
Munday conducted the research along with the university's Coral Centre of Excellence, the Australian Institute of Marine Science, Georgia Institute of Technology and the National Geographic Society.
The loss of survival instinct, according to Munday, is due to oceans becoming more acidic. Of all the carbon dioxide that is released into the atmosphere, 30 percent is eventually absorbed by the ocean. The amount of acid in the waters by the coral reef is expected to spread throughout the entire ocean over the next hundred years, AFP reported.
The waters around the Papua New Guinea coral reef are already naturally acidic. But the fish have been unable to adapt to the increasing acidity.
"They didn't seem to adjust within their lifetime," Munday told AFP. "That tells us that they don't adjust when they are permanently exposed to these higher carbon dioxide levels and we would have to think about whether adaptation would be possible over the coming decades."