Longspine thornyhead lives in the Pacific Ocean where it ranges from the southern tip of Baja California in Mexico up to the Aleutian Islands of Alaska, at depths from 370 m to 1600 m. In British Columbia, this species occurs along the continental slope at depths between 500 and 1,600 m. The predominant population group can be found in DFO fisheries management region WCVI (West Coast Vancouver Island), with two smaller observed groupings in the Tidemarks and Rennell regions further north.The species prefers soft sand or mud bottoms in deep-water environments characterized by low productivity (slow growth), high pressure, and reduced oxygen concentrations.

Longspine thornyhead, a rockfish species belonging to the scorpionfish family, is a slow growing fish that is adapted for survival in deep waters where oxygen concentrations are minimal and water pressure is high. This species has a reddish body and some black on its fins, grows to 35 cm in length, and features large eyes and strong, sharp head spines. Longspine thornyheads stop growing at a length of about 30 cm and an estimated age of 25 to 45 years. It is not yet known how long longspine thornyheads can live, although estimates range from 45 to 70 years.