Australian spotted jellyfish (Phyllorhiza punctata) are thought to have gotten to the Gulf of Mexico by hitching a ride on a ship coming through the Panama Canal. They have invaded the Mississippi River in May, and are expected to do great harm to commercially valuable fish populations. The jellyfish eat fish larvae and eggs, as well as competing with young fish for the same food resources.
Photograph courtesy of USGS
Caption information from the Florida Department of Environmental Protection and the U.S. Geological Survey.