ICES considers the species blue whiting (Micromesistius poutassou) in ICES Subareas 1–9, 12, and 14 as a single stock for assessment purposes (ICES 2012). However, scientific evidence supports 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).

One other report by ICES notes that the species' distribution has changed, likely due to environmental conditions, but such changes did not affect proportions between TAC management areas (ICES 2017). This profile refers to the NE Atlantic assessment unit until a formal definition of the two distinct stocks is established.