The Taxonomic Status and Histological Features of Gonads of the Giant Redfish of the Genus Sebastes

There are four redfish species of the genus Sebastes in the North Atlantic: beaked redfish S. mentella Travin, 1951; Norway redfish S. viviparus Kroyer, 1845; golden redfish S. norvegicus (Ascanius, 1772); and Acadian redfish S. fasciatus Storer, 1856. However, the taxonomic status of the so-called “giant” Sebastes, redfish with an average length over 60 cm of the Irminger Sea, Iceland, and Greenland slopes, remains unresolved. Using histological and genetic analysis, we studied 17 giants that were collected in the North Atlantic (Irminger Sea) in 2011–2021. Based on the results of analysis of nuclear (RP2 S7) and mitochondrial (D-loop) DNA sequences, which are species-specific for North Atlantic Sebastes, it was established that at least some giants are hybrids between S. norvegicus and S. mentella. A descendant of S. norvegicus and the hybrid S. norvegicus × S. viviparus was also revealed. The results of histological analysis confirmed the previously published data on the sterility of giant females, but at the same time showed that the reproductive ability of male is apparently retained.