Why is it sometimes such a big deal when species end up in the wrong places? On Naked Oceans this month we explore marine invasions and find out how people shift species around the oceans, what problems this causes, and what can be done to stop them. We visit the Caribbean to get the lowdown on a notorious ocean alien, the lionfish, and find out how the best policy could be "Eat 'em to beat 'em". Janet Voight tells us about her recent report that warns deepsea explorers to be very careful not to pick up any unwanted hitchhikers. And in Critter of the Month we ask Miriam Goldstein to tell us if she were a marine species, which'd she be and why.