Canada.com - Scientists play down price tag on invasive species in Great Lakes

A new U.S. report says foreign species carried into the Great Lakes by ships are causing tens of millions of dollars in damage to the ecosystem. However, Canadian experts are questioning the figures, saying you cannot easily put a price on damages caused by invasive species. While they say the problem is real, the lakes are in no danger of dying anytime soon.

Anthony Ricciardi, an associate professor at McGill University in Montreal and an invasive species biologist, says this is not the first time someone has tried to put a dollar amount on economic damages, but assigning a price is not easy.

"It's hard to put a price tag on it, because some kind of indication of cost is better than having no indication at all," said Ricciardi. "We know we have a fishery worth over $500 million in the Great Lakes, but contaminants are not solely from the ships and we cannot tell how many are. We cannot put an exact number on things that cannot be measured."