They have green backs, pink bellies and are only about 2 inches in diameter. The invasive green crab has been destroying clam and scallop populations from South Carolina to Maine, since they were introduced here two centuries ago.

Every year, monarch butterflies make an amazing journey from Canada and New England all the way down to Mexico. It’s an ecological wonder celebrated by all three countries — but recently, scientists have noticed a dip in the number of butterflies making the trip.