The Patagonian toothfish is a species of notothen found in cold waters between depths of 45 and 3,850 m in the southern Atlantic, Pacific, and Indian Oceans and Southern Ocean on seamounts and continental shelves around most Subantarctic islands.
A close relative, the Antarctic toothfish (Dissostichus mawsoni), is found farther south around the edges of the Antarctic shelf, and a Marine Stewardship Council-certified fishery is active in the Ross Sea. Both species are sometimes marketed as Chilean sea bass.
The average weight of a commercially caught Patagonian toothfish is 7–10 kg (15–22 lb), depending on the fishery, with large adults occasionally exceeding 100 kg (220 lb). They are thought to live up to 50 years and to reach a length up to 2.3 m (7.5 ft). Several commercial fisheries exist for Patagonian toothfish, which are detailed below.