The little known Japanese skeleton shrimp Caprella mutica is a very powerful and successful invader. A study published this week in the scientific journal Hydrobiologia found that the amphipods had spread from their Pacific origin in the waters off Japan to twenty-nine non-native locations around the globe, spanning both hemispheres. They are often associated with aquaculture sites, marinas and oil rigs, where they may occur in staggering densities, suggesting that ballast water and transfer with Pacific oysters are likely vectors. In Scotland C. mutica had first been identified in 2002 and has since been found over a wide area. Lead authorcoconducted the work as part of a NERC-funded PhD studentship at SAMS UHI which she successfully completed in November 2006.