Striped marlin are present in the east from off Torres Strait to Tasmania, and in the west from the North West Shelf to about 125°E off southern Australia (Ref. 6390).

Stock structure: The stock structure of striped marlin in the Pacific Ocean is uncertain. Analyses of catch-effort data with morphometrics (Ref. 30364) and time (Ref. 30379) provided some evidence for separate northern and southern hemisphere stocks. However, evidence from catch-effort and tagging data and studies of spawning areas, body proportions and changes in body length related to geography (Ref. 30443) suggests that there is general movement of striped marlin between several widely separated areas of the Pacific. Some fish may range further than others, yet the overall diffusive movements (not migration) could permit management of different core areas of high catch rates as if they represented separate stocks (Ref. 30443). The stock structure of striped marlin in the Indian Ocean is unknown.

Commercial fishery: Striped marlin are targeted by Japanese fleets of drifting longline vessels in the eastern Pacific, and off Japan and New Zealand. They are also targeted in tropical waters of the Australian Fishing Zone by these fleets, as are yellowfin tuna (Thunnus albacares), bigeye tuna (T. obesus) and broadbill swordfish (Xiphias gladius). New South Wales does not allow the fish to be sold commercially, except for export (Ref. 9987, 6390) and striped marlin may not be sold in Western Australia.

Striped marlin caught in the Japanese longline fishery off eastern Australia range from 70-170 kg processed weight. Those in the west coast fisher range from 10 kg to 140 kg, with modes at 21-27 kg and 50-60 kg. Maximum catch rates occur from September to November: on the east coast offshore between Gladstone and the Queensland-New South Wales border; and in the west, offshore between Exmouth and Broome. Highest catch rates of striped marlin occur further offshore than those of black marlin (Makaira indica). Off Western Australia (and other areas off the species’ distribution) the best fishing grounds for striped marlin are centred at the boundary of currents and where the sea surface temperature is 20-22°C (Ref. 30446).

The Australian (domestic) catch of striped marlin by longline fleets is very much less than the catch by the Japanese longline fleet.

The Japanese longline boats range in size up to 350 t and 45 m in length and each boat generally spends about 30-60 days in the Australian Fishing Zone during its fishing campaign in the south-west Pacific. The longlines comprise a main line 70-110 km long with a series of branch lines bearing a total of about 3000 hooks. One set of a single main line is made in any 24 hour period, and traditionally the lines are set to fish at between 50 m and 150 m depth.

The primary market for striped marlin is the Japanese raw fish (‘sashimi’) and (‘sushi’) market. Striped marlin are the most valuable of all marlins. The prices paid for fresh striped marlin easily exceed those paid for any other species of billfish and are similar to those paid for bigeye tuna.

Recreational fishery: Striped marlin are mainly caught by trolling or by handlining from anchored or drifting boats. Lures are live or dead bait of oily fish such as mackerel and small tunas (Scombridae), kingfish (Seriola species) or mullet (Mugilidae). Striped marlin are fished over continental shelf and slope waters. Generally the recreational fisheries for striped marlin are located off Queensland from about Mooloolaba to Cape Moreton, from about off Cape Hawke in New South Wales to Point Hicks in eastern Victoria and off Tasmania from Cape Barren Island to St Helens. The Western Australian fishery for striped marlin is centred off Exmouth. Most striped marlin are caught off the active New South Wales gamefishing centres of Port Stephens, Sydney and Bermagui. The largest striped marlin angled in Australia as of 1993, was 172 kg, from off Bermagui in 1988 (Game Fishing Association of Australia record).

Up until mid 1992, 812 striped marlin had been tagged under the New South Wales Fisheries Research Institute’s gamefish tagging program, 410 of them off New South Wales. Six striped marlin had been recaptured.

Resource status: The results of production models based on Pacific-wide catches from 1952 to 1980 and in 1985 suggest that striped marlin stocks are not over-fished. They are either close to an optimal level of fishing (Ref. 30364) or are below it (Ref. 30379). The status of the resources off eastern or western Australia is unknown. Also Ref. 2334.