Identification and biology
The samson fish, Seriola hippos, is the heavyweight of the Australian amberjacks: deeper and broader than a kingfish, pale silver to purple-brown above, with a yellow stripe along the lateral line and a fight that DPIRD’s fact sheet credits with a world-class sportfishing reputation. The same sheet sets out the biology: samson fish grow fast, to 60 cm in two years, reach at least 175 cm, 55 kg and 32 years, and females mature at 89 cm and four years. The species lives off southern Australia from Shark Bay round to the Yorke Peninsula, and patchily on the east coast from Moreton Bay to Jervis Bay, but it is commoner off Western Australia than anywhere else. They are treasured for their fight rather than their table quality, so most are released.
Where they live through the year
The Rottnest aggregations form from November to February on the wreck ground west of the island that fishers call the Rottnest Barges, and the boats jig them on the calm days. DPIRD’s tagging, more than 10,000 fish between 2001 and 2007, showed that the fish return in winter to resident grounds south or east of Rottnest, and two tagged at Rottnest were recaptured in South Australia about 2,500 km away. Outside the aggregation the fish are caught through the warm months around the inshore reefs and the wrecks of the south-west, and in the south as a by-catch of kingfish and reef fishing. The West Coast demersal closure does not stop them: DPIRD lists samsonfish among the boat-fishing species anglers may still catch in the West Coast bioregion during the closure.
The mistakes that cost fish
Going undergunned: a big samson fish on a kingfish outfit is a long fight and a tired fish at the end of it, and the jig fishery runs on heavy gear so the fight is short and the release good. Fishing without a release plan: DPIRD notes that spawning fish do not feed actively in the aggregation and may leave it in poor condition, needing extra care when released, although samson fish vent gas from their swim bladder as they rise and in one study 93 per cent survived release from 80 to 133 metres. Jigging too slowly; the researchers had to entice them with flashing metal jigs. And going out without the swell forecast: the ground is exposed and the calm summer days are the only days.
Reading the report for samson fish
The wind row and the Bureau’s swell forecast, which the report does not carry, decide the day; the sea breeze ends most Perth mornings on the water by early afternoon. Pressure matters little at depth. The water temperature estimate tracks the warm season the aggregation follows. The species card rates the month on the Western Australian waters; the calendar shows summer and autumn as the season.
Tackle setups
| Situation | Setup | Why it works |
|---|---|---|
| Jigging the aggregation | 1.7 to 1.9 m jig rod rated 24 to 37 kg, 37 kg braid, 60 to 80 kg leader, 250 to 400 g knife jig | Heavy gear keeps the fight short so the fish is released in good condition |
| Inshore reef by-catch | 2.1 m rod rated 15 to 24 kg, 24 kg braid, 40 to 60 kg leader, live bait or 150 g jig | The fish met while kingfish or reef fishing along the south-west coast |
| Release | Release weight rigged, 1 kg on a heavy line | A spent fish from the aggregation goes back faster on a weight |
Playbook by water temperature
The plan the daily report picks for samson fish in each band; the water temperature on each page is a seasonal estimate for its type of water and says so.
Hot water (over 27 °C)
Heavy jigging over the deep reef and the aggregation sites early; live baits on the wrecks.
Warm water (18 to 27 °C)
Prime. Knife jigs and big plastics worked over the reef edges and the bait schools.
Cool water (10 to 18 °C)
Fewer fish, deeper; jig the wrecks and the deeper lumps on the calm days.
Cold water (under 10 °C)
Scarce inshore; a deep-water fish for the dedicated.
Month by month
Activity for the southern year, 1 slow to 5 peak; January is midsummer. Current month highlighted.
Waters we cover for samson fish
16 Australia waters carry samson fish on their species card, each with a daily report.
Common questions
Where is the samson fish aggregation?
West of Rottnest Island, on the wreck ground fishers call the Rottnest Barges, from November to February, as DPIRD’s fact sheet describes it; the Perth and Rottnest pages rate the month.
Can I keep samson fish during the WA demersal closure?
Samsonfish are among the boat-fishing species DPIRD lists as still open in the West Coast bioregion during the demersal closure. Bag and size limits apply; the Western Australia hub links the rule.
Are samson fish good to eat?
Edible, but DPIRD’s fact sheet says they are treasured for their fighting ability rather than their eating quality, and most are released; heavy gear keeps the fight short for the fish that go back.
Pages checked
- marinewaters.fish.wa.gov.au/mwwp/wp-content/uploads/2019/06/CR511-Fisheries-Fact
- marinewaters.fish.wa.gov.au/resource/fact-sheet-samson-fish
- dpird.wa.gov.au/environment-and-sustainability/sustainable-fisheries/demersal-sc
The facts on this page were checked against these pages, from the agencies, park services and operators that manage the water on 27 September 2026; anything we could not verify was taken out.