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").
Fish Hook River and Potato Lakes, respectively. Potato Lake collects Hay Creek, which flows from northeastern Becker County, draining a region of lakes. The Fish Hook River flows in the Northern Lakes and Forests ecoregion, which is characterized by conifer and hardwood forests on flat and rolling till plains and outwash plains. The river's fish population is dominated by suckers, but walleye and northern pike are also present. Fish Hook River The Fish Hook River, also spelled Fishhook River, is a tributary of the Shell River, long, in north-central Minnesota in the United States. The river's source, Fish Hook Lake, collects short tributaries