Previous attempts to identify different populations of European sprat (Sprattus sprattus) during the 1980-1990s were unsuccessful (Nielsen 1994). Gulf of Lyon and the Adriatic Sea populations have the “biggest genetic distance” within the Mediterranean and any population differentiation was found between the Baltic Sea, the North Sea, and the Bay of Biscay (Debes et al. 2008).

Genetic analysis showed a clear genetic distinction between the NE Atlantic Ocean and the Baltic Sea and a high differentiation of the Adriatic Sea population from all northern samples (Limborg et al. 2012). More recently, a “complex population structure is considered across the species’ distribution” (Limborg et al. 2012). Nevertheless, ICES recommends further studies to clarify this structure (e.g., the apparent overlap between the North Sea and the English Channel populations). This profile considers only Baltic sprat in the ICES subdivisions 22-32. 

In addition, FishSource considers the following sprat assessment units currently defined by ICES: Celtic Sea and West of Scotland (Subarea 6 and Divisions 7a–c and f–k); English Channel (Divisions 7d,e); and North Sea and Skagerrak and Kattegat (Subarea 4 and Division 3a).