Hāpuku are grey in colour with silvery white underbellies, with juveniles generally being blue in colour. They have 10 dorsal spines running along their back, a rounded anal fin and rounded pectoral fins, and a large, powerful, square-shaped tail. Its lower jaw protrudes from the top, and their very large eyes are adapted for hunting and inhabiting low-light conditions. Differs from Bass by a more slender body, pointed head and protruding lower jaw.

Deepwater species. Adults occur generally over rough ground from the central shelf (about 100 m) to the shelf edge and down to the upper slope. Juveniles are found in surface waters, perhaps school in association with drifting weed.

Feed on barracouta and pilchards, in addition to various bottom-dwelling fish.

Hāpuku are a large, slow growing, long-lived species. They reach sexual maturity between 10 and 13 years and have lifespans up to 60 years. They can grow as large as 100 kg, but are usually found around the 25 kg mark. They have an average size of 80–100 cm but can grow up to 180 cm in length.
Prized food fish. Exploitation for over 70 years has depleted stocks especially inshore.

Paxton, J.R., D.F. Hoese, G.R. Allen and J.E. Hanley, 1989. Pisces. Petromyzontidae to Carangidae. Zoological Catalogue of Australia, Vol. 7. Australian Government Publishing Service, Canberra, 665 p.