Macrourus berglax shrimps, amphipods, polychaete worms, bivalve molluscs, isopods, brittle stars, other echinoderms and comb jellies. The roughhead grenadier is a slow growing fish. The females mature at an age of about 14 years and a length of while males reach maturity at a length of . The potential fecundity of the female is 17,000 to 56,000 eggs. The eggs are laid in batches and spawning takes place at any time of year, with a peak in late winter and early spring. The roughhead grenadier is landed as a by-catch when fishing for Greenland halibut ("Reinhardtius hippoglossoides") and Atlantic halibut ("Hippoglossus hippoglossus").
Smoked fish the increased use of the idiomatic expression "red herring", references to the smoked fish product in this manner declined. A more common current name for it is kippers, or kippered herring. Kippered herring traditionally undergoes further processing (soaking and cooking) before consumption. Arbroath Smokies (haddock) and Traditional Grimsby smoked fish (haddock and cod) have both received Protected Geographical Indication status from the European Commission, which restricts use of the name to fish that is processed using specific methods within a defined geographical area. Other smoked fish products from the UK include Finnan Haddie and Bloater. Smoked fish Smoked fish is