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Bathymetric barriers promoting genetic structure in the deepwater demersal fish tusk ( Brosme brosme )
Author(s) -
KNUTSEN HALVOR,
JORDE PER ERIK,
SANNÆS HANNE,
RUS HOELZEL A.,
BERGSTAD ODD AKSEL,
STEFANNI SERGIO,
JOHANSEN TORILD,
STENSETH NILS CHR.
Publication year - 2009
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2009.04253.x
Subject(s) - demersal zone , biology , pelagic zone , population , genetic structure , gene flow , range (aeronautics) , ecology , bathymetry , habitat , fishery , ridge , oceanography , genetic variation , paleontology , geology , biochemistry , materials science , demography , sociology , gene , composite material
Population structuring in the North Atlantic deepwater demersal fish tusk ( Brosme brosme ) was studied with microsatellite DNA analyses. Screening eight samples from across the range of the species for seven loci revealed low but significant genetic heterogeneity ( F ST = 0.0014). Spatial genetic variability was only weakly related to geographical (Euclidean) distance between study sites or separation of study sites along the path of major ocean currents. Instead, we found a significant effect of habitat, indicated by significant differentiation between relatively closely spaced sites: Rockall, which is surrounded by very deep water (>1000 m), and the Mid‐Atlantic Ridge, which is separated from the European slope by a deep ocean basin, were differentiated from relatively homogeneous sites across the Nordic Seas. Limited adult migration across bathymetric barriers in combination with limited intersite exchange of pelagic eggs and larvae due to site‐specific circulatory retention or poor survival during drift phases across deep basins may be reducing gene flow. We regard these limitations to gene flow as the most likely mechanisms for the observed population structure in this demersal species. The results underscore the importance of habitat boundaries in marine species.