Blue ling feed on fish (flatfishes, gobies, rocklings) and crustaceans and benthic invertebrates.

[1] A barbel is a sensory organ that helps the fish find its food, given limited light near the bottom of the water column.

[2] The Blue ling is divided into three different stocks, the first including blue ling in Icelandic and Greenland waters (bli.27.5a14), the second in Celtic Seas, Faroe grounds, Rockall, Hatton banks and Mid-Atlantic Ridge (bli.27.5b6712), and the third in the Northeast Atlantic, North Sea, Skagerrak and Kattegat areas (bli.27.123a4), see figure.

The study also suggests further splits between fjord groups due to isolation and genetic drift over generations, separating the eastern Norwegian subareas from the western areas (Atlantic basin).

[6] They live to be 20–30 years old, though determining age is difficult due to methods involving embedding and cutting thin otolith slices to count growth rings.

[7] Blue ling are commercially fished in the North-Eastern Atlantic, which has decreased their populations through the 1990s in all described stock.

[1] In Norwegian waters, blue ling are allowed as bycatch only (10%), which has had the same effect as closed areas regulation given avoidance of spawning habitat by fisheries.

[2] Fleets specifically targeting ling are allocated a total allowable number of fishing days to be used in the demersal area, with a recommended minimum landing size of 60 cm.

[8][7] In 2020, an agreement between Norway and the Faroe Islands permitted 2500 tons of ling as bycatch in bottom fishery in Faroese waters.

Continued exploitation of the blue ling is mostly influenced by regulation that is aimed at other species like cod or haddock.