ICES considers several different units of anglerfish for assessment and management purposes:

1) Anglerfish in Division 3a (Kattegat and Skagerrak), Subarea 4 (North Sea), and Subarea 6 (West of Scotland and Rockall) (Lophius piscatorius and L. budegassa);
2) Angler (L. piscatorius) and blackbellied angler (L. budegassa; this profile) in Divisions 7b–k and 8a,b,d (Southern Celtic Sea and Bay of Biscay);
3) Angler and blackbellied angler in Divisions 8c and 9a (Cantabrian Sea and Atlantic Iberian waters).

However, the boundaries between stocks are not based on biological criteria, according to studies carried out in genetic and morphometric analysis (Duarte et al., 2004 and Fariña et al., 2004 in ICES, 2014a). In the unit covered by this profile the two species: angler, or white anglerfish (L. piscatorius) and blackbellied angler (L. budegassa) are assessed and advised by ICES as a single assessment unit (ICES, 2014c). Angler (L. piscatorius) in Divisions 4a, Division 6a and Rockall might in fact extend into 7, 5 or 2a, although there is currently insufficient evidence to support an extension of the stock area (ICES, 2013).