North Pacific shellfish–including snails and other mollusks–may blaze a path across the Arctic Ocean to the North Atlantic if the sea ice melts in coming decades as predicted, a pair of scientists said today.

Mollusks traveled the northern passage when the Arctic was last ice free, about 3.5 million years ago, during a warm stage of the Pliocene, which spanned 5.3 to 1.8 million years ago, the scientists say.