The voracious eaters can reach 100 pounds, and experts worry they'd be able to out-compete native fish for food, threatening the lakes' $7 billion fishing industry.

Tuesday's report shows that fertilized Asian carp eggs can incubate in waterways that are only 26 km (16 miles) long. That's far shorter than the 100 km (62 miles) of undammed water that researchers previously thought the drifting eggs needed before they could hatch.

The USGS says the floating eggs are slightly heavier than water, which means they will sink — and, generally, die — if they get trapped in a slow-moving river, lake or stream. But the stretches of uninterrupted, moving water give the eggs a better chance of survival.