Open AccessThe making of a genetic cline: introgression of oceanic genes into coastal cod populations in the Northeast Atlantic
Author(s) -
Per Erik Jorde,
Mats Brockstedt Olsen Huserbråten,
Bjørghild Breistein Seliussen,
Mari Skuggedal Myksvoll,
Frode Vikebø,
Geir Dahle,
Asgeir Aglen,
Torild Johansen
Publication year - 2021
Publication title -
canadian journal of fisheries and aquatic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 153
eISSN - 1205-7533
pISSN - 0706-652X
DOI - 10.1139/cjfas-2020-0380
Subject(s) - cline (biology) , gadus , atlantic cod , introgression , gene flow , arctic , pelagic zone , picoplankton , oceanography , fishery , biology , ecology , geography , genetic variation , geology , population , gene , biochemistry , demography , phytoplankton , sociology , nutrient , fish <actinopterygii>
Coastal Atlantic cod (Gadus morhua) in the Northeast Atlantic has seen a continuous decline since the industrialization of the coastal fishery, and management needs to address the spatial and temporal complexities of coexisting cod stocks. Toward that end, genetic analyses and oceanographic modelling of coastal and oceanic cod larval drift patterns were combined to elucidate the mechanisms responsible for an observed genetic cline over a >1500 km stretch along the coast of Norway. The results indicate that the north–south cline in coastal cod represents an extended contact zone between genetically divergent North Sea and Northeast Arctic cod and is maintained by two-way gene flow: by northward drift of pelagic eggs and larvae and by southward spawning migrations of Northeast Arctic cod. Computer simulations verify that the genetic cline can be established rapidly if gene flow into coastal populations is substantial. The shape of the cline, on the other hand, was found to be largely insensitive to the total amount of gene flow and therefore carries little information on extent of gene flow into and among coastal populations.