Arripis trutta

Species of fish

Arripis trutta, known as the Australian salmon in Australia and as kahawai in New Zealand, is a South Pacific marine fish and one of the four extant species within the genus Arripis, native to the cooler waters around the southeastern Australian coasts and the New Zealand coastline. Other common names for this species include Eastern Australian salmon, bay trout, blackback salmon (or just "black back"), buck salmon (or "buck"), cocky salmon, colonial salmon, newfish and salmon trout. Although it is referred to as "salmon" in Australian English and its species epithet trutta is Latin for trout, it is not related to true salmons or trouts, which belong to the family Salmonidae of the order Salmoniformes. All Arripis species belong to the family Arripidae of the order Perciformes.

Arripis trutta was first formally described in 1801 as Sciaena trutta by Marcus Elieser Bloch and Johann Gottlob Theaenus Schneider with the type locality given as the Cook Strait.

Arripis trutta is a streamlined fish with a long and slender body. There is a bony ridge edge of bone beneath and in front of each eye which has obvious serrations in smaller individuals. In larger fish the scales feel smooth. The lobes of the caudal fin are equivalent in length to the head. These fish are dark bluish green dorsally and silvery white ventrally. The juveniles have golden bars on their upper flanks and these break up into large spots as the fish matures. The pectoral fin is vivid yellow and the caudal and spiny part of the dorsal fin both have a blackish margin. There are 9 spines and 15–17 soft rays in the dorsal fin and 3 spines and 9–10 soft rays in the anal fin. The maximum total length recorded is although they are commonly a total length of around and the maximum recorded weight is .

Arripis trutta is found in the southwestern Pacific Ocean mostly around the littoral waters of the Tasman Sea and Bass Strait. They are also found around the Chatham Islands and Kermadec Islands

Arripis trutta are preyed on by larger marine predators such as seals, dolphins and sharks. The feeding schools push the smaller fish they are preying on towards the surface, making them accessible to seabirds, In this way, this species has an important ecological role in facilitating transfer of energy among the upper levels of the pelagic food chain in inshore ecosystems. The Australian population of this species spawns in the surf zone between Lakes Entrance in southeastern Victoria and Bermagui in New South Wales South Coast in the late spring and summer. They first spawn when they are around four years old and have attained a length of They can live for up to 26 years. In New Zealand the principal commercial fishing areas are north of Kaikōura in the South Island, off the coast of North Island and in the Cook Strait. Fisheries New Zealand manages that nation's fishery to maintain the population of A trutta at roughly 52% of the stock which was present before modern commercial fisheries began and in 2019 the population was well above that target.

Arripis trutta are highly prized by recreational fishers, especially for anglers fishing from beaches and rocks. Anglers tend to catch this species using light tackle or by fly fishing and it is said to be a "sporting catch".