Several studies have been conducted to understand the life history, migratory behaviour, body morphology, and genetics to determine the population structure of anglerfish but further research is needed (Crozier, 1987; Duarte et al., 2004; Fariña et al., 2004; Blanco et al., 2008; Landa et al., 2008). In lack of a clear stock structure within the region the assessment units assumed by ICES, not based on genetic or biological data (GESSAN, 2002; Duarte et al., 2004; Fariña et al., 2004; ICES, 2010; Cañás et al., 2012), are here used:

1) Skagerrak, Kattegat, North Sea and West of Scotland including Divisions IIa, IIIa, Subareas IV and VI where both Lophius species are assessed together;

2) Southern Celtic Sea and Bay of Biscay including Divisions VIIb-k and VIIIab where there are separated ICES advices for (white) angler and blackbellied angler but the species are managed jointly;

3) Bay of Biscay and Atlantic Iberian waters including Divisions VIIIc and IXa in where both species are captured and landed together so two linked but separated ICES advices are published for (white) angler and blackbellied angler (ICES, 2014a,b);

4) Icelandic in Division Va only for L. piscatorius (MRI, 2015).