Lionfish (Pterois volitans and P. miles) originally hail from the Indo-Pacific, but arrived in the western Atlantic in the 1980s or 1990s. No one knows exactly how the fish invaded Atlantic waters, but home aquarists who dump unwanted lionfish into the ocean may have been the cause, according to the National Oceanic and Atmospheric Administration (NOAA).
Lionfish are adept hunters of gobies, which are small, schooling fish that tend to hover near rocks and the seabed, making them easy to herd and corner. The lionfish threat has helped put some goby species on the vulnerable and endangered species lists, Baldwin and her colleagues wrote in their new paper. But little is known about lionfish-hunting behavior in deep reefs, between about 165 feet and 985 feet (50 and 300 meters) down. In many areas, this level is known as the “twilight zone” because only dim light can penetrate that much water.
On Feb. 9, 2015, the submersible Curasub launched from Substation Curaçao and captured video of a school of about 50 orange-striped gobies hanging out near a rock wall 384 feet (117 m) down. In the video, a lionfish slowly cruises over the school with its fins spread wide, striking at the school with a sudden surge. The gobies fled to join a second, nearby school of the same species, but it was no use. About a minute after the first strike, the lionfish cornered the larger school against the rock wall and struck again, seeming to swallow some fish.
P. incendius has now been collected or at least observed in deep reefs near Curaçao, Cominica and Honduras, the researchers reported. It does not seem to be in immediate danger of extinction, despite the lurking threat of the lionfish. But just the fact that lionfish are apparently hunting small fish in deep reefs has scientists alarmed.