ICES considers blue whiting in ICES Subareas 1–9, 12, and 14 as a single stock for assessment purposes (ICES 2012). However, there is scientific evidence to support the hypothesis of two components (Keating et al. 2014, Pointin and Payne 2014) with some degree of mixing in the central overlap area (Mahe et al. 2016). The ICES Stock Identification Methods Working Group (SIMWG) reviewed this evidence in 2014 and recommended that blue whiting be considered as two stock units (ICES 2014). A recent report by ICES notes that there have been changes in the distribution of the species, likely linked to environmental conditions but that such changes did not affect proportions between TAC management areas (ICES 2017). Until a formal definition of the two distinct stocks, this profile refers to the NE Atlantic assessment unit.