Fish ‘exhibit a fatal attraction to predators’ in acidified ocean
Fish reared in water acidified by CO2 may become “fatally attracted” to the smell of their predators, say scientists. A team studying the effects of acidification – caused by dissolved CO2 – on ocean reefs found that it leaves fish unable to “smell danger”. Young clownfish that were reared in the acidified water became attracted to rather than repelled by the chemical signals released by predatory fish. The findings were published in the journal Ecology Letters. Danielle Dixson from James Cook University in Queensland, Australia, led the study. She and her colleagues tested orange clown fish larvae that were raised in water with the same slightly alkaline pH as their ocean reef habitat, and those raised in more acidic water. … In the test, the fish reared in normal water avoided the stream of water that their predators had been swimming in. They detected the odour of a predator and swam away from it. But, Ms Dixson said, fish raised in the more acidic water were strongly attracted to both the predatory and the non-predatory flumes. The researchers say that their study shows that fish larvae “might exhibit a fatal attraction to predators at CO2 and pH levels that could occur in our oceans by 2100 on a business-as-usual scenario of greenhouse gas emissions”. …
