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").
Paralichthys adspersus 1842 as "Hippoglossus kingii", which would have placed it in the left-eye flounder family. However, the description of "H. kingii" has been determined to lack sufficient information to absolutely determine which species it describes and is thus considered ambiguous and therefore is not valid. Paralichthys adspersus Paralichthys adspersus, the fine flounder, is a species of large-tooth flounder native to the eastern Pacific Ocean, along the continental shelf from the coast of Ecuador in the north to the coast of Peru in the south. It is a medium-sized flatfish, growing up to 70 cm in length, with females typically being larger