Bull Rout

• It produces antifreeze proteins that let it live in Arctic waters below the freezing point of fresh water.
• The male guards the eggs for weeks, fanning them with his fins and defending them from predators.
• When lifted out of the water it swells its body and flares the spines on its gill covers, a defensive mechanism that gives fishermen painful jabs.
• It manufactures antifreeze proteins that allow it to live in water at freezing temperature or below, the same solution the Antarctic fishes arrived at on their own.
• Its antifreeze is intracellular, which is unusual: it protects the inside of the cells, not just the body fluids, and it has been patented for preserving chilled foods and inhibiting ice recrystallisation.
• The male guards the clutch: the eggs are laid in a mass among the rocks and he watches over it for about five weeks until they hatch.
• It is used as a sentinel species for pollution in Greenland. At old lead and zinc mines, its mucus secretion has been measured increasing the closer the fish is to the mine.
• Its head is enormous and covered in spines, hence its many English common names, almost all of them unflattering.

Skeleton type

Vertebrate - internal bony skeleton (fish)

Habitat & environment

Rocky and weedy bottoms of the North Atlantic and the Arctic, from 0 to 450 m

Sexual maturity

Size at first maturity 17.8 cm (range 15-30)

Sources consulted: FishBase (Froese & Pauly, eds.); Lista Roja de la UICN; Dang et al. (2019), Science of the Total Environment; patente US 6429293

Best time: From December to March, the spawning season