Scientists from Canada say only a small number of Asian carp might be enough to pose serious threats to native fish in the Great Lakes.
Kim Cuddington of the University of Waterloo says there's a 50-50 chance of the bloated carp gaining a foothold if only 10 of them find their way into the Great Lakes.
If 20 fish make it through, she says the probability of major damage could be 75-percent under some conditions.
An electronic barrier is keeping the Asian carp out of Lake Michigan for now, but Cuddington says it's not likely that the fast-growing fish can be kept out of the Great Lakes forever.
She says the amount of time to create a large population of bighead and silver carp would depend on how old the carp are when they spawn.