August 6, 2018 — There have been numerous wake-up calls about the effects of climate change on marine life. As ocean waters heat up, they are bleaching corals. Growing levels of carbon dioxide are acidifying seawater, which is degrading the shells and skeletons of sea organisms. The rising temperatures are prompting fish to migrate to colder waters, even causing them to shrink.
Now climate change is starting to affect their sense of smell, a phenomenon that will worsen in the coming years if global warming continues unabated, according to new research. A sense of smell is indispensable to fish. They use it to find food, detect imminent danger and elude predators, to find safe environments and spawning areas, even to recognize one another.
To lose it could threaten their very survival. If this happens, it also would mean big trouble for the fishing industry, tourism and, most importantly, global nutrition, since many of the world’s people — including its poorest — depend on fish for food.
“Future levels of carbon dioxide can have large negative effects on the sense of smell of fish, which can affect fish population numbers and entire ecosystems,” said Cosima Porteus, a researcher at the University of Exeter and author of the study, which appears in the journal Nature Climate Change.
“This can be prevented, but we must reduce carbon emissions now before it’s too late,” Porteus says.
Carbon dioxide combines with seawater to produce carbonic acid, which makes the water more acidic. Since the Industrial Revolution, oceanic CO2 has risen by 43 percent and is projected to be two and a half times current levels by the end of this century, according to the scientists.