Broadgilled Hagfish

The broadgilled hagfish (Eptatretus cirrhatus) is a jawless fish in the family Myxinidae found around New Zealand and southern Australia, and is notable for reaching a larger size than most other hagfish species. Its common name refers to its comparatively wide, prominent gill pore openings. As with all hagfish, it lacks jaws, a bony vertebral skeleton, and paired fins, relying on a cartilaginous skull and a rasping tongue-like structure to feed on carrion. The species lives on soft sediment across a wide depth range, from relatively shallow coastal waters down to several hundred meters on the continental shelf and slope. It is one of the better-studied Southern Hemisphere hagfish species, having been the subject of research into hagfish reproduction and slime chemistry.

• Thick, elongated, scaleless body, mottled grey-brown to purplish, among the largest hagfish species
• No jaws or paired fins; only a low, rounded tail fin
• Slit-like mouth surrounded by short barbels
• Broad, prominent row of gill pore openings along each side, giving the species its name
• Adult length commonly 60-100 cm, notably larger than most other hagfish

The broadgilled hagfish is distinguished from smaller regional hagfish by its greater overall size and the width and prominence of its gill pore openings, a key trait reflected in its common name.

Broadgilled hagfish are found around New Zealand and southern Australia, occurring on soft mud or sand seabeds across a broad depth range from shallow coastal waters down to around 900 meters on the continental shelf and upper slope. They tolerate a wider range of depths and temperatures than many other hagfish species, allowing them to occupy both nearshore and deeper offshore habitats. Individuals typically burrow partially into sediment when inactive, using the loose substrate for shelter. Their wide depth tolerance and regional abundance have made them one of the more accessible hagfish species for scientific study in the Southern Hemisphere.

Broadgilled hagfish are solitary, opportunistic scavengers that feed on dead or dying fish and invertebrates on the seafloor, using a rasping tongue-like structure to tear and consume tissue, sometimes burrowing into a carcass from the inside. When threatened, they release large volumes of fibrous slime from pores along their body, which expands in water to clog the gills of potential predators, and can tie their bodies into a knot to remove excess slime or gain leverage. Broadgilled hagfish are simultaneous hermaphrodites and lay a small number of large, yolky, tough-shelled eggs directly onto the seafloor, without passing through a distinct larval stage, a reproductive pattern shared by all hagfish.