The first expedition to use a deep-diving submersible to study the Atlantic Ocean lionfish invasion found something very disturbing -- at 300 feet deep, there were still significant populations of these predatory fish, and they were big. Big fish can reproduce much more efficiently than their younger, smaller counterparts, and lionfish can travel. This raises significant new concerns in the effort to control this invasive species that is devastating native fish populations on the Atlantic Coast and in the Caribbean Sea....