Genomic Insights Into Population Structure and Demographic History of White Anglerfish (Lophius piscatorius)...

Understanding population structure and clarifying species boundaries are essential for the sustainable management of exploited marine species. Although genomic resources for shallow-water taxa have expanded rapidly, open-water species remain comparatively understudied. Here, we present a comprehensive genomic analysis of the white anglerfish (Lophius piscatorius), a commercially important species that occupies a wide depth range. We examined genetic structuring and verified species identity across its distribution range in the North Atlantic and Mediterranean. We combined whole-genome sequencing of selected individuals with targeted SNP genotyping of 897 specimens from 35 locations. Our results support a panmictic or nearly panmictic population of white anglerfish throughout the Northeast Atlantic, consistent with earlier studies, here extended northward to about 68° N. We found no evidence of local adaptation or selection. Like earlier studies, we detected apparently misclassified specimens of the closely related black anglerfish (L. budegassa) and extensive hybridization with up to 20% hybrids in local samples from around the Celtic Sea and nearby waters. Most or all hybrids appear to be first generation (F1), with a few potential backcrossed individuals of less certain identification. Demographic analyses indicate a recent colonization of the North Atlantic, with black anglerfish diverging more recently and maintaining a smaller effective population size. These results underscore the value of integrating genomic tools into monitoring frameworks to improve species identification, delineate population units, and inform sustainable fisheries management.