Black Hagfish

The black hagfish (Eptatretus deani) is a jawless fish in the family Myxinidae found on the deep continental slope of the northeastern Pacific Ocean, from British Columbia to Baja California. It is named for its consistently dark, near-black coloration, which distinguishes it from many paler-bodied hagfish species. Like other members of its family, it lacks jaws, a bony vertebral skeleton, and paired fins, relying instead on a cartilaginous skull and a rasping tongue apparatus for feeding. Black hagfish are bottom-dwelling scavengers that live at considerable depth on soft sediment, well below the reach of sunlight. They are considered one of the more common deep-water hagfish species along the Pacific coast of North America and are frequently collected in deep-set baited traps.

• Long, cylindrical, scaleless body, uniformly dark grey to blackish-brown all over
• No jaws or paired fins; only a low, continuous paddle-shaped tail fin
• Slit-like mouth surrounded by short sensory barbels
• Row of external gill pore openings along each side of the body
• Adult length typically 40-63 cm

The black hagfish is distinguished from similar Pacific hagfish species mainly by its notably dark, nearly uniform blackish body coloration, in contrast to the grayer or pinkish tones seen in relatives such as the Pacific hagfish, along with subtle differences in gill pore count.

Black hagfish live on the deep continental slope of the northeastern Pacific Ocean, ranging roughly from British Columbia south to Baja California. They occur on soft muddy or silty bottoms at depths generally between about 100 and 950 meters, in cold, dark water well beyond the reach of sunlight. Individuals typically remain partially burrowed in sediment during periods of inactivity, emerging to scavenge when food becomes available. Because they inhabit such deep, offshore environments, black hagfish are rarely encountered except through deep trawls or baited traps, and much of what is known about their biology comes from such fishery and research sampling.

Black hagfish are solitary, deep-water scavengers that spend extended periods buried in soft sediment, emerging to feed on dead or dying fish and invertebrates that reach the seafloor. When disturbed, they release fibrous slime from pores along their body that expands rapidly in water, deterring predators by clogging gills. They can tie their bodies into a knot to work slime from their skin or gain leverage while burrowing into a carcass to feed. Black hagfish are believed to be simultaneous hermaphrodites, like other hagfish, and lay a small number of large, tough-shelled eggs directly onto the seafloor rather than passing through a larval stage.