Fish lose sense of smell in polluted waters

Fish lose sense of smell in polluted waters
http://www.environmentalhealthnews.org/ehs/news/2013/fish-smell

"Fish in lakes tainted with metals are losing their sense of smell, stoking concern among experts that the problem could devastate populations. But if the fish can just get into cleaner water – even if they've been exposed to pollutants their whole life – they start sniffing things properly again, according to new research out of Canada. Fish use their sense of smell to find mates and food, and to avoid getting eaten. It helps them navigate their often murky world, and it is necessary for their growth and survival. But when metals contact fish nostrils, the neurons shut down to protect the brain. "We've tested everything from leeches to water fleas to several species of fish," said Canadian scientist Greg Pyle. "Every species and every metal we've observed has had effects at low, environmentally relevant concentrations.""