Molecular identification of redfish (genus Sebastes) in the White Sea indicates patterns of introgressive hybridisation

The rare occurrence of redfish (genus Sebastes) in the White Sea encouraged Rolskii et al. (Polar Biol 43:385–389, 2020) to investigate the species identity of two animals captured near the Sredniy Island at 40 m depth. They reported that their morphological description proved unreliable and that genetic evidence “clearly demonstrated” these redfish belong to S. norvegicus. This was inferred using the S7 and the mitochondrial control region genes. However, while their S7 matched one S. norvegicus reference sequence, the S. norvegicus mitochondrial reference sequences used to infer species identity were previously shown to cluster with S. mentella. Therefore, both of their redfish samples belong to a S. norvegicus × S. mentella (deep-pelagic) hybrid which presents an interesting perspective into the complex species dynamics in this group.