ICES Journal of Marine Science: Journal du Conseil Advance Access originally published online on January 10, 2008
ICES Journal of Marine Science: Journal du Conseil 2008 65(2):216-225; doi:10.1093/icesjms/fsm187
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Evidence for population structuring of blue whiting (Micromesistius poutassou) in the Northeast Atlantic
1 Molecular Ecology Research Group, Department of Life Sciences, Galway-Mayo Institute of Technology, Dublin Road, Galway, Ireland
2 Sea Fisheries Institute Gdynia, Kollataja 1, 81-332 Gdynia, Poland
3 Norwegian University of Science and Technology, Trondhjem Biological Station, N-7493 Trondheim, Norway
* Correspondence to E. Gosling: tel: +353 91 742324; fax: +353 91 758412; e-mail: elizabeth.gosling{at}gmit.ie
Was, A., Gosling, E., McCrann, K., and Mork, J. 2008. Evidence for population structuring of blue whiting (Micromesistius poutassou) in the Northeast Atlantic. – ICES Journal of Marine Science, 65: 216–225.Many marine fish species are characterized by large population sizes, strong migratory behaviour, high fecundity, and pelagic eggs and larvae that are subject to passive transport by ocean currents, all factors that tend to reduce the rate of development of genetic partitioning among localized populations. The blue whiting (Micromesistius poutassou) is a commercially important gadoid that exhibits all these characteristics, although to date there has been little evidence of genetic heterogeneity except at the latitudinal extremes of its range in the NE Atlantic. Genetic variation was analysed at five microsatellite loci in 16 samples, 14 comprising spawning adults, collected along the continental shelf from 44°N to 60°N, a distance of
1900 km. Although pairwise FST values were low (0.0–0.040; mean 0.0097), more than 40% of the estimates were significant, with Celtic Sea and Bay of Biscay samples significantly differentiated from samples from the Porcupine Bank, Hebridean Shelf, Sulisker Bank, and Papa Bank. There was also significant differentiation between samples taken in different years on Rockall Bank. Mantel tests revealed no significant isolation by distance. We used a landscape genetics approach, which combines spatial and genetic information, to detect barriers to gene flow. Four zones of lowered gene flow were identified, generally in concordance with hydrographic patterns, fish spawning behaviour, and the simulated transport of larvae in the NE Atlantic Ocean.
Keywords: blue whiting, gene flow, genetic differentiation, landscape genetics, Micromesistius poutassou, microsatellites
Received 5 July 2007; accepted 25 November 2007; advance access publication 10 January 2008.