Greenland halibut (Reinhardtius hippoglossoides) in the North Atlantic are genetically homogeneous

Abstract

Greenland halibut (Reinhardtius hippoglossoides) have become of great importance to the Canadian fishery since the moratorium on northern cod (Gadus morhua), and an understanding of stock relationships among populations at the northern and southern extremes of their commercial range is crucial for proper management. We compared mitochondrial DNA sequence variation among fish taken from thoughout the Northwest Atlantic (Flemish Pass, the Grand Banks, Davis Strait, and Northwest Greenland) with samples from the Gulf of St. Lawrence, Iceland, and Norway. Within a 401 base pair portion of the cytochrome b gene, 22 genotypes were identified. Three of these occur at frequencies >10% and in the same relative abundances in all samples (except the Gulf of St.Lawrence). Genotype proportions do not differ significantly among samples, and genetic subdivision among samples (measured by the coancestry coefficient theta ) is nil. Genetic distances among samples are not related to geographic distribution: pairwise differences between the Gulf sample and other western Atlantic samples exceed those for trans-Atlantic comparisons. These data suggest that there is sufficient mixing of Greenland halibut, not only within the NAFO regulatory area, but among sites in the North Atlantic generally, to prevent the development or maintenance of genetically independent stocks.

Genotyping of marine viral haemorrhagic septicaemia virus isolated from the Flemish Cap by nucleotide sequence analysis and restriction fragment length polymorphism patterns

“…Although the Flemish Cap is certainly far away from the European waters where isolates belonging to this genotype have been obtained, the spreading of the virus could be explained if migratory patterns of Greenland halibut are taken into account. This species is widely distributed in the North Atlantic and can cover extreme distances during migration, from Norway and Iceland to the Grand Banks of Newfoundland (Vis et al 1997).…”

“…Although the Flemish Cap is certainly far away from the European waters where isolates belonging to this genotype have been obtained, the spreading of the virus could be explained if migratory patterns of Greenland halibut are taken into account. This species is widely distributed in the North Atlantic and can cover extreme distances during migration, from Norway and Iceland to the Grand Banks of Newfoundland (Vis et al 1997).Due to the sampling procedure, the low variability observed among the GH isolates (at least regarding this sequence) can be extrapolated to the whole population of Greenland halibut and suggests that the strains observed must share a common and relatively recent origin. On the other hand, inclusion of GH isolates in Genotype 3 will increase the variability within this genotype.…”

Phylogeographic mitogenomics of Atlantic codGadus morhua: Variation in and among trans‐Atlantic, trans‐Laurentian, Northern cod, and landlocked fjord populations

“…Unlike terrestrial and freshwater species that frequently exhibit strong population genetic structure from barriers to gene flow such as rivers, waterfalls, mountains, and deserts, marine species typically experience fewer and less formidable physical obstacles. While some species are restricted by habitat requirements or feeding habits (e.g., tropical reef fishes) and show clear population genetic structure (Shulman & Bermingham, 1995), pelagic species often have wide distributions, large population sizes, high fecundity, and extensive gene flow (Palumbi, 1992), and tend to display weak population structure in the absence of natal philopatry (Carr, Duggan, Stenson, & Marshall, 2015; Castro et al., 2007; Vis, Carr, Bowering, & Davidson, 1997; Ward, 1995). …”

Depth and temperature preferences of the deepwater flatfish Greenland halibut Reinhardtius hippoglossoides in an Arctic marine ecosystem

“…The Greenland halibut Reinhardtius hippoglossoides has become an important commercial fish species, particularly in the Northwest Atlantic (Bowering & Brodie 1995, DFO 2008a. This benthic flatfish inhabits deep (typically 400 to 1000 m and as deep as 2200 m) (Vis et al 1997, Bowering & Nedreaas 2000 and cold (~0 to 6°C) (Bowering & Nedreaas 2000) waters in northern latitudes (> 45° N) in the Arctic, Atlantic and Pacific Oceans (Bowering 1984, Dyck et al 2007). Older fish usually move to greater depths, where they spawn (Bristow 1992, Gundersen et al 2010.…”