Southern hake
Merluccius australis, the southern hake, is a species of fish from the family Merlucciidae, the true hakes. It is found in the southern Pacific and Atlantic Oceans with two disjunct populations, one around southern South America and the other in the waters around New Zealand.
Merluccius australis has a more slender body compared to other species of Merluccius, with a short head which is makes up around a quarter of its standard length and a protruding lower jaw with some visible teeth. The anterior dorsal fin has a single spine and 9 to 12 fin rays and the posterior dorsal fin has 39 to 45 fin rays. The anal fin has 40 to 46 fin rays and the pectoral fins are long and thin, but they do not reach as far as the origin of anal fin in specimens longer than 50 cm standard length. The caudal fin margin is normally truncate, but in smaller specimens it can be slightly emarginate. The scales are small and there are 144 to 171 scales along the lateral line. They have a steel grey back which is tinged with blue, paler on sides, and a silvery white belly with dark fins. It grows to a maximum length of 160 cm but lengths of between 60 cm and 100 cm are more commonly recorded.
Merluccius australis has two distinct populations one in New Zealand and the other in the eastern South Pacific and western South Atlantic. The New Zealand population is found over the Chatham Rise, Campbell Plateau and around South Island north to the East Cape, the South American population extends from Chiloé Island south to 59°S in the Pacific, around Cape Horn and north to 38°S in the South Atlantic. It is also found off the Falkland Islands.
Merluccius australis occurs at depths between 415 and 1 000 m with temperatures at the bottom of 5.8 to 8.0 °C off New Zealand and 62 to 800 m with bottom temperatures 3.8 to 9.0 °C in South American waters. The adults are probably migratory, moving south to feed during the Austral summer and returning north in the winter to spawn. Off South America spawning takes place from May to August south of 47°S, in three separate areas. The spawning areas are situated in fjords and channels. They reach sexual maturity at around 65 cm in length for males and 85 cm for females, around 6 years of age. The sex ratio is skewed towards females. The adults are predatory, feeding on southern blue whiting, whiptails, nototheniids and squid. Off New Zealand population the population spawns from July to August in the waters west of South Island at depths from 800 to 1000m, and here they also feed mainly on fish, particularly gadoids but also on squid, krill and benthic invertebrates. On the northern part of the Campbell Plateau spawning occurs between September and November and at the Chatham Rise between November and January. They can live as long as 28 years.
