Every Easter, hundreds of fishermen visit the south-west corner in the hope of catching a ‘salmon’. These are no ordinary ‘salmon’ – these are Western Australian Salmon Arripis truttaceus. It is an important distinction, because they are not true salmon, in fact not even vaguely related. They belong to a family of fishes (Arripidae) found only in Australia and New Zealand, and there are only four species. A sister-species, the eastern Australian Salmon Arripis trutta occurs in south-east Australia and New Zealand (where it is called Kahawai). Another species, Giant Kahawai Arripis xylabion, is found around the islands north of New Zealand. The fourth species is the much smaller Australian Herring Arripis georgianus.
Western Australian Salmon Arripis truttaceus. Photo: Debra Moore. Image copyright Debra Moore.
Western Australian Salmon occur from north of Perth to the western parts of Victoria and Tasmania. Adults form large schools along exposed beaches and rocky reefs and juveniles utilise shallow bays and estuaries as nursery areas. Western Australian Salmon grow to at least 96 cm in length and may weigh in excess of 9 kg. They eat mostly small baitfish and are eaten by sharks, dolphins and, of course, humans.
Their arrival in the south-west from about March is all about sex - most individuals of this species accumulate in the area between Cape Leeuwin and Busselton in late autumn and early winter to spawn when the eastward flowing Leeuwin Current is strongest, and eastward-directed winds are dominant, enabling transport of pelagic larvae to the south-east. The larvae settle out along the entire southern coast of Australia but most ‘float’ all the way to Victoria and Tasmania. They grow up in nursery grounds between South Australia and Tasmania for some three to four years before moving westwards to WA, where they live in schools around the Hopetoun and Esperance areas. In mid-winter, when the spawning run in the south west is finished most fish migrate back to these southern WA waters.
School of Western Australian Salmon. Photo: Barry Hutchins. Image copyright of WA Museum.