There are no studies about the genetic structure of surmillet population in Northeast atlantic. However, a study was made to differentiate stocks, based on the shape of the otoliths. The study area was divided into six sectors: the NS (North Sea; ICES Division IVabc), the EEC (Eastern English Channel; ICES Division VIId), the WEC (Western English Channel; ICES Division VIIe), the CS (Celtic Sea; ICES Division VIIf,g,h,j), the NBB (North Bay of Biscay; ICES Division VIIIa) and the SBB (South Bay of Biscay; ICES Division VIIIb) (Heessen 2010).