Florida has often been cited as the likely location of the introduction, but the new research suggests some lionfish may have come from the more southern areas.
Lionfish are native to the Indo-Pacific region, and were likely brought to the US via the pet trade.
The spiny fish is well known as a predatory invasive species that negatively impacts its non-native environment, disrupting marine food webs as they prey in coral reef ecosystems on invertebrates and fish, including game fish juveniles, such as snappers and groupers.
Researchers analysed red lionfish samples from fourteen countries and territories in the Greater Caribbean and Western Atlantic in an effort to better understand the invasive species' population structure and dispersal patterns.
Margaret Hunter, a geneticist from the US Geological Survey and one of the study authors, said: "The more we know about this species and its progression, the more we can help resource managers and others fighting the invasion be prepared to help control lionfish colonisation in new locations.
"Ultimately, any information gleaned from this species could be applied to managing and assisting with eliminating future invasive species."
Researchers found that unique regional genetic patterns separated the studied area into northern and southern regions, with the split occurring near the Bahamas. One rare genetic strain was found in only a few samples in the southern region, but was pervasive in the north.
"Dispersal against the flow of ocean currents may explain why we see this rare strain in the south, but even if that is the case, additional support for multiple introductions exists; the genetic patterns found in this study support the idea of multiple introductions, and could be due to additional releases in the south," said John Butterfield, lead author of the study.
Continued releases would increase the potential for more genetically diverse red lionfish to join the current population, which could counter future removal efforts or allow them to more rapidly expand their range beyond current boundaries.
The broad dispersal of red lionfish may in part be due to their reproductive habits.
Females can spawn up to once every four days, which could result in one female releasing up to two million eggs a year. Following spawning, larvae can disperse long distances via ocean currents, for up to 35 days.
In the United States, federal and state agencies are working together to help combat this invasive fish through the Aquatic Nuisance Species Task Force.
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