Wide-ranging phylogeographic structure of invasive red lionfish in the Western Atlantic and Greater Caribbean
The red lionfish (Pterois volitans) is an invasive predatory marine fish that has rapidly expanded its pres- ence in the Western Hemisphere. We collected 214 invasive red lionfish samples from nine countries and territories, including seven unpublished locations. To more compre- hensively evaluate connectivity, we compiled our d-loop sequence data with 846 published sequences, resulting in 1,060 samples from 14 locations. We found low nucleo- tide diversity (π = 0.003) and moderate haplotype diversity (h = 0.59). Using haplotype population pairwise ΦST tests, we analyzed possible phylogeographic breaks that were pre- viously proposed based on other reef organisms. We found support for the Bahamas/Turks/Caicos versus Caribbean break (ΦST = 0.12) but not for the Northwestern Carib- bean, Eastern Caribbean, or US East Coast versus Bahamas breaks. The Northern Region had higher variation and more haplotypes, supporting introductions of at least five haplo- types to the region. Our wide-ranging samples showed that a lower-frequency haplotype in the Northern Region domi- nated the Southern Region and suggested multiple introduc- tions, possibly to the south. We tested multiple scenarios of phylogeographic structure with analyses of molecular vari- ance and found support for a Northern and Southern Region split at the Bahamas/Turks/Caicos versus Caribbean break (percentage of variation among regions = 8.49 %). We found that Puerto Rico clustered with the Southern Region more strongly than with the Northern Region, as opposed to previous reports. We also found the rare haplotype H03 for the first time in the southern Caribbean (Panama), indicat- ing that either secondary releases occurred or that the low- frequency haplotypes have had time to disperse to extreme southern Caribbean locations.