Although he doubted butterfish would polish off the jellyfish and end the problem, at least fishermen would have a tasty commercial species to replace the anchovies. As people get more mobile and the world economy makes us more global, the chance for introduction gets a lot higher. Hickey said the imported species can also include harmful algae that cause red tides or harmful bacteria. One debatable point is whether every exotic species causes harm. The periwinkle first appeared in Nova Scotia 100 years ago.
Scientists theorize it was imported by lovers of escargot.
O'Connor is studying the latest import, the Asian shore crab, also known as the Japanese crab. Probably brought to local shores in ship ballast water, the crabs could also have come from worms imported from Vietnam in bait. They were first noticed on Cape May, N.J., in 1988. By 1994, they were spotted with some frequency in Buzzards Bay. Last summer's survey found the Asian crab to be well-established from the Cape up along the North Shore.