The problem of differences in the rate of evolution among different animal or plant species has been intensely discussed in recent years, so the question of the validity of a so-called molecular clock hypothesis is very relevant. We have performed a search for publications describing median networks, which include haplotypes of mitochondrial genes for closely related boreal and arctic fish species (or those who settled through the Arctic). In all seven cases included into our analysis, the rate of nucleotide substitutions in Arctic taxa or taxa that settled through the Arctic during their evolutionary history was higher, and this difference was statistically significant. Therefore, the formation of new fish taxa in polar latitudes is accompanied by a rapid evolution of mitochondrial DNA that apparently reflects their adaptation to the new environment. In addition, speciation in Arctic fishes is usually accompanied by multiple chromosome fusions. Therefore, both our data and the data of other researchers provide solid reasons to doubt in the validity of the molecular clock hypothesis.

The evolutionary history of North Atlantic Sebastes redfishes was reconstructed as a result of studying the mitochondrial DNA D-loop sequences of Sebastes redfishes inhabiting the North Atlantic and the Arctic Oceans. It was shown that speciation of these redfishes occurred in several stages. During the first stage, the ancestor of the Norway redfish ( S. viviparus ) diverged from the common ancestor species in the process of allopatric speciation. The ancestor of Acadian redfish ( S. fasciatus ) diverged from the common ancestor as it evolved. Budding speciation in the species that would later evolve into golden redfish ( S. norvegicus ) resulted in the emergence of the beaked redfish ( S. mentella ). Paleoclimatic events seem to have played the key role in species divergence as they caused habitat fragmentation allowing isolated groups to become genetically distinct in the meantime. The conducted analysis of the speciation of Sebastes redfishes brings into question the generality of widely accepted views on fish sympatric speciation. It also serves as an argument against the molecular clock hypothesis.

The paper aims at giving a brief review of the population structure, abundance and biomass dynamics of beaked redfish of the Irminger Sea obtained during the trawl acoustic surveys and analytical assessment. The adequacy of the current fisheries management measures for redfish in NEAFC is assessed. It was shown, that recent findings of the foreign genetic research apparently contradict to the relevant population structure for beaked redfish of the Irminger Sea applied in ICES, which specifies four stocks of the species. The ICES’ position of the depressed shallow pelagic and deep pelagic redfish stocks lacks substantial evidence from the results of the surveys in 2018–2021 and analytical assessment carried out by the Russian experts for the single redfish stock. The results allow assessing the current state of the stock as ‘good’. Thus, ICES/NEAFC recommendations that there shall be no directed fisheries neither for the shallow pelagic redfish stock nor the deep pelagic redfish stock in the Irminger Sea and adjacent waters until 2024 are insufficiently substantiated and need to be revised.