Lionfish have already taken over parts of the Atlantic Ocean and new research, just published in Marine Biodiversity Records, shows that they’re beginning to invade the Mediterranean. They’ve been spotted throughout Cyprus and are quickly spreading to other parts of the sea.
There are two species of invasive lionfish, Pterois volitans and Pterois miles. P. miles had occasionally been spotted in the Mediterranean but these sightings weren’t verified until this new study. Researchers collaborated with divers and fisherman to find out where the fish had been found. They took photos and videos, recording the location and date of the sighting. At least 19 individual lionfish were spotted.
Lionfish pose an ecological threat for a number of reasons. They’re hardy and adaptable, allowing them to invade new areas. Lionfish are also generalist predators, consuming anything that’ll fit in their mouths. They have venomous spines and very few natural predators. This combined with rapid maturation allows them to quickly colonize an area, reducing biodiversity in the reef ecosystem. Released aquarium pets may be the source of the original population. There have been efforts to control and eradicate lionfish, including promoting the fish as a meal option. So far, none of these efforts have made a measureable impact on the wild populations.
The authors believe that rising sea temperatures in the Mediterranean are responsible for allowing the lionfish to colonize the area. If this is the case, the problem will only get worse. The researchers recommend the establishment of lionfish removal programs throughout the Mediterranean, beginning with the coast of Cyprus. One possibility is to establish healthy populations of the dusky grouper, a native fish that is immune to the venomous spines of lionfish. Groupers are one of the only natural predators of both P. volitans and P. miles. The paper notes that some of the lionfish spotted were engaging in mating behaviors, pointing to a need to develop population control programs as soon as possible.
Demetris Kletou et al. A lionfish (Pterois miles) invasion has begun in the Mediterranean Sea. Marine Biodiversity Records (2016).