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

1997 ◽  
Vol 54 (8) ◽  
pp. 1813-1821 ◽  
Author(s):  
M L Vis ◽  
S M Carr ◽  
W R Bowering ◽  
W S Davidson
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Genetic Distances ◽  
Greenland Halibut ◽  
Western Atlantic ◽  
Grand Banks ◽  
The North ◽  
Greenland Halibut Reinhardtius Hippoglossoides ◽  
The North Atlantic ◽  
Reinhardtius Hippoglossoides

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.

Population genetic structure in the North Atlantic Greenland halibut (Reinhardtius hippoglossoides): influenced by oceanic current systems?

2007 ◽  
Vol 64 (6) ◽  
pp. 857-866 ◽  
Author(s):  
Halvor Knutsen ◽  
Per Erik Jorde ◽  
Ole Thomas Albert ◽  
A Rus Hoelzel ◽  
Nils Chr. Stenseth
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
North Atlantic ◽  
Geographic Distance ◽  
Ocean Currents ◽  
Greenland Halibut ◽  
The North ◽  
Greenland Halibut Reinhardtius Hippoglossoides ◽  
The North Atlantic ◽  
Reinhardtius Hippoglossoides

We report statistically significant genetic structure among samples of Greenland halibut (Reinhardtius hippoglossoides), rejecting the null hypothesis of panmixia in the North Atlantic. The species appears instead to be subdivided into partially isolated populations, with some evidence for isolation by distance. However, there is a dichotomy between transatlantic sample comparisons and those within a regional current system, even when geographic distance is similar. Calculating geographic distance along the flow of ocean currents gave a more linear correlation with genetic differentiation than straight-line geographic distances, suggesting that gene flow follows ocean currents. We hypothesize that gene flow is mediated by drift of eggs and larvae with ocean currents, a hypothesis that is consistent with the extended pelagic phase of Greenland halibut larvae. This implies an important role for ocean currents in shaping the genetic structure of this and potentially other deep-sea species.

A Review of the Morid Fish Genus Lepidion of the North Atlantic With First Records of Lepidion eques from the Western North Atlantic

1970 ◽  
Vol 27 (3) ◽  
pp. 457-498 ◽  
Author(s):  
Wilfred Templeman
Keyword(s):  
North Atlantic ◽  
Sexual Maturity ◽  
Head Length ◽  
Western Atlantic ◽  
Morphometric Characters ◽  
Northeast Atlantic ◽  
West Greenland ◽  
Biological Station ◽  
The North ◽  
The North Atlantic

Seventeen specimens of Lepidion eques (Günther) taken by the Fisheries Research Board of Canada St. John's, Nfld., Biological Station are apparently the first records of the species from the western Atlantic west of West Greenland. Comparison with specimens from the northeast Atlantic shows some differences in averages of meristic and morphometric characters, but with overlapping ranges in these characters.Comparison of these North Atlantic L. eques with the Mediterranean Lepidion lepidion (Risso) revealed that although closely related, these species are separable on the bases of the smaller orbit diameter in relation to the head length and especially by the relatively larger postorbital length in L. lepidion. Lepidion guentheri (Giglioli) is distinctly different from these two species in some meristic and many morphometric characters. Lectotypes of L. eques and L. guentheri are designated. Various incorrect or doubtful records of Lepidion are discussed. Two giant lepidions reported recently from the northeast Atlantic as L. guentheri are tentatively assigned to Lepidion schmidti Svetovidov, a species hitherto known only from Japan.The distributions of the North Atlantic species of Lepidion are discussed and information is provided on sexual maturity.

Decadal Relationship between European Blocking and the North Atlantic Oscillation during 1978–2011. Part I: Atlantic Conditions

2015 ◽  
Vol 72 (3) ◽  
pp. 1152-1173 ◽  
Author(s):  
Dehai Luo ◽  
Yao Yao ◽  
Aiguo Dai
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Western Europe ◽  
Storm Track ◽  
Western Atlantic ◽  
Atlantic Sector ◽  
The North ◽  
Nao Index ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract Both the positive and negative phases of the North Atlantic Oscillation (NAO+ and NAO−, respectively) and atmospheric blocking in the Euro-Atlantic sector reflect synoptic variability over the region and thus are intrinsically linked. This study examines their relationship from a decadal change perspective. Since the winter-mean NAO index is defined as a time average of instantaneous NAO indices over the whole winter, it is unclear how the activity of European blocking (EB) events can be related to the variation of the positive mean NAO index. Here, this question is examined by dividing the winter period 1978–2011 into two decadal epochs: 1978–94 (P1) with an increasing and high NAO index and 1995–2011 (P2) with a decreasing and low NAO index. Using atmospheric reanalysis data, it is shown that there are more intense and persistent EB events in eastern Europe during P1 than during P2, while the opposite is true for western Europe. It is further shown that there are more NAO+ (NAO−) events during P1 (P2). The EB events associated with NAO+ events extend more eastward and are associated with stronger Atlantic mean zonal wind and weaker western Atlantic storm track during P1 than during P2, but EB events associated with NAO− events increase in western Europe under opposite Atlantic conditions during P2. Thus, the increase in the number of individual NAO+ (NAO−) events results in more EB events in eastern (western) Europe during P1 (P2). The EB change is also associated with the increased frequency of NAO− to NAO+ (NAO+ to NAO−) transition events.

Sign in / Sign up

Export Citation Format

Share Document