Inhabit southern Australian waters from Wide Bay in Queensland to Shark Bay, Western Australia (Ref. 7300), including Bass Strait and Tasmania (Ref. 27930).

Stock structure: Electrophoretic studies of protein variation in jack mackerel have shown that Australian fish are genetically distinct from New Zealand fish. Within Australian waters there appears to be a distinct subpopulation in the west and 2 or more subpopulations in the southeast (Ref. 9361).

Commercial fishery: Prior to the establishment of the jack mackerel fishery in 1993, a number of fishing trials were conducted. Purse seine nets were used in pelagic fishing trials off New South Wales and eastern Tasmania between 1946 and 1950. Purse seining was also tried near Lakes Entrance in the mid 1970s (Ref. 27933). In 1973, a fishery for jack mackerel was commenced by a company operating from Triabunna in Tasmania, where their fishmeal processing plant was located. Approximately 6300 t were caught in 1973-74 from waters between southern New South Wales and southern Tasmania. All of the catch was processed into fishmeal. The operation closed in 1974.

In 1985, another venture aimed at fishmeal production commenced at Triabunna. Subsequently, there was a rapid rise in landings of jack mackerel, peaking at almost 40,000 t in 1986-87. The fishery has continued and up until 1993, was the source for over 90% of Australian jack mackerel landings. The catch was taken almost exclusively using purse seine nets, usually 500 m to 800 m in length and up to 70 m depth. Vessels vary in size between 25 m and 47 m, and up to 7 boats fish at some time during the fishing season (Ref. 27934).

The jack mackerel purse seine fishery targets surface or near surface schools. Schools are located using a spotter plane or sonar and depth sounder. The main fishing area is near the central east coast of Tasmania although catches are taken from Flinders Island in the northeast to Macquarie Harbour on the west coast. Some fish are taken off the northern Tasmanian coast between Devonport and George Town on the Tamar River. A few purse seine vessels target jack mackerel in State waters off Lakes Entrance in eastern Victoria and Port Macdonnell in South Australia.

Alternative methods for catching jack mackerel in New South Wales, Victoria and Tasmania are demersal otter trawling, midwater otter trawling and fixed tidal traps. The fisheries in New South Wales and Victoria are localised and sporadic.

The Tasmanian fishing season lasts from October to May. Catches early in the season are normally taken in the north and later along the east coast, where an increase in numbers of surface schools results in greater catches. Catches are mostly taken during the day. The abundance of jack mackerel schools seems to exhibit great inter-annual variability. This varation may be caused by changes in the species' schooling behaviour which in turn reduces their catchability by purse seine fishing.

The 2 main bycatch species of jack mackerel fishery are redbait (Emmelichthys nitidus) and blue mackerel (Scomber australasicus). They constitute about 5% of the annual landings from this purse seine fishery. Small numbers of Peruvian jack mackerel (Trachurus murphyi) have also been recorded from Tasmanian jack mackerel catches in the same period (Ref. 27939).

The majority of the jack mackerel catch is processed into fishmeal for livestock and aquaculture feeds. The Tasmanian fishery is the main source of domestic fishmeal production. Some of the jack mackerel is sold as bait for rock lobster (Palinuridae) or longline fisheries. Very little is consumed by humans in Australia but significant quantities are used as pet food.

Recreational fishery: Jack mackerel are commonly caught by recreational anglers throughout their Australian distribution. They are mainly caught using rod-and-line or handline methods. The largest jack mackerel recorded by the Australian Anglers Association weighed 1.7 kg and was caught in New South Wales.