Acidic oceans — Fish losing survival instinct
sydney — Fish are losing their survival instinct — even becoming attracted to the smell of their predators — as the world’s oceans become more acidic because of climate change, new research said.
The study of fish in coral reefs off the coast of Papua New Guinea — where the waters are naturally acidic — showed the animals’ behaviour became riskier.
“Fish will normally avoid the smell of a predator, that makes perfect sense,” lead author Professor Philip Munday from Australia’s James Cook University said. “But they start to become attracted to the smell of the predator. That’s incredible.
“They also swim further from shelter and they are more active, they swim around more. That’s riskier behaviour for them — they are more likely to be attacked by a predator.”
Munday said the research, published in the journal Nature Climate Change, was important given that about 30 per cent of the carbon dioxide released into the atmosphere is ultimately absorbed by the ocean, a process which results in the seas becoming more acidic. Acidification around the reefs studied is at levels predicted to become ocean-wide by the end of the century as the climate changes.
Munday said the fish appeared to have failed to adapt to the conditions, despite living their whole lives exposed to high levels of carbon dioxide. —