Samson Fish WA: The Rottnest Jigging Guide

Most WA fish put up a fight. The samson fish files a formal complaint. Hook a decent one in deep water off Rottnest and the first run is less a fight than a negotiation you are losing, conducted at speed, with your gear as collateral. Sambos are the brute-force end of the Seriola family — bigger-shouldered and worse-tempered than the kingfish they share a page with in the rule book — and they have built one of the most distinctive sportfisheries in the state right on Perth’s doorstep.

This is a guide to chasing samson fish in WA: what they are, where the fishery actually is, the tackle that survives them, and whether the fish you’ve just won is worth keeping.

What a Samson Fish Actually Is

Samson fish (Seriola hippos) are a large pelagic predator endemic to southern Australia, and a close cousin of the kingfish. Commonly 5–15kg, the Rottnest deepwater fishery produces fish well over 25kg, and they top out past 50kg. One tagged fish went from 7.3kg to roughly 25kg in six years — they grow fast and they grow big.

The identification trap is the rest of the family. Three lookalike Seriola sit in WA’s large pelagic finfish group:

• Samson fish — deep-bodied, blunt-headed, broad-shouldered. The bruiser.
• Yellowtail kingfish (Seriola lalandi) — sleeker, with a clear yellow tail and a yellow stripe running down the flank.
• Amberjack (Seriola dumerili) — similar build to samson but typically caught in deeper, warmer water.

If you can’t tell which one is on the deck, it barely matters for the rules — all three share the same minimum size and the same combined bag limit. It matters a lot for bragging rights, so learn the difference.

Where the Fishery Is

The samson fish story in WA is really the Rottnest story. The biggest known aggregations of samsons anywhere gather around deepwater structure off Rottnest during their spawning run, and at their peak — roughly November to February — they stack up in their thousands. This is a boat-based, deep-water fishery: anglers jig metal lures in 100m of water and occasionally deeper, and it once drew jigging fanatics from across the globe.

It is also overwhelmingly a catch-and-release fishery. Samsons release well when handled correctly, the bigger ones aren’t reliable eating, and there’s no point killing a 30kg fish you can’t legally keep three of anyway.

• Rottnest Island — the deepwater marks off the island are the engine room of the WA samson fishery. Boat access only for the proper jigging grounds; check the conditions before committing to the run across.
• Two Rocks Marina and Ocean Reef Marina — northern launch points for boats working the deeper reef lines off the metro coast.
• Hillarys Boat Harbour — a central metro launch for trailer boats heading out to structure.

Smaller samsons turn up on shallower reef and around heavy structure, which brings the shore angler into it — barely.

The Shore-Based Reality

Land-based samson fish in Perth are rare, and the ones you do hook usually end with a straightened hook or a frayed leader wrapped around something you’ll never see. The deep-water rock walls and pylons are where it occasionally happens.

• North Mole — the deeper water off the Fremantle moles holds the odd samson, usually as a heartbreak by-catch for someone targeting something more reasonable.
• Fremantle Fishing Boat Harbour — structure and current where a live bait fished hard on the bottom can occasionally find one.

If you’re fishing the shore for sambos, fish for them on purpose with gear that’s far too heavy for everything else around, or accept that the hookup is a bonus and the result is a story about the one that took your jig and your dignity.

The Rules

Samson fish sit in WA’s large pelagic finfish category, which has a combined daily bag limit of 3 fish per fisher — that single limit of 3 is shared across the whole group, so two samsons and a Spanish mackerel is your lot. The minimum legal size is 600mm. Amberjack and yellowtail kingfish carry the same 600mm minimum and draw from the same bag of 3.

Boat fishing in WA also requires a Recreational Fishing from Boat Licence, and since the real samson fishery is boat-based, that one applies to almost everyone chasing them properly. Limits and licence rules change — confirm the current numbers in the DPIRD recreational fishing rules before you head out.

Gear: Built to Lose, Hoping to Win

Samson fish destroy under-gunned tackle, so the deepwater jigging rigs are deliberately brutal.

Jigging setup (the Rottnest game)

• Jigs: knife jigs from 115g to 400g. In the deep marks around 100m, run the heavy end — 250–400g — to hold the strike zone in current. A bit of luminescence helps in the dark down there.
• Rod: short jigging stick, 1.5–1.8m, with the backbone to lift a fish off the bottom.
• Reel: large spin or overhead with a strong drag, line classes 30–80lb (PE4–6 braid).
• Leader: 80–150lb to survive chafe on rough structure when the fish dives.
• Hooks: heavy assist hooks rated to the jig — single or twin assists at the head end are standard for this style.

Bait / shore setup

• The heaviest spin or overhead you own — think rock-fishing kingie gear, not jetty tackle.
• PE4–6 braid, 80–100lb leader, 8/0–10/0 hooks.
• Live bait — herring, mullet or scad — or a whole squid, fished hard on the bottom near the deepest structure you can reach.

When a samson eats, the first three seconds decide everything. Lock the drag and turn its head, or it reaches the reef and the negotiation is over.

Timing and Conditions

The spawning aggregations off Rottnest peak November to February, which is the window most jigging trips target. Outside that, samsons are around year-round on deeper structure but in nothing like the same numbers.

Fish the tide changes early or late in the day, and lean into the period around the new moon — that’s when the deep-water bite reliably switches on. Before you book a charter or fuel the boat, check swell, wind and tide for Rottnest Island on BiteCompass; the run across exposed water decides whether the day happens at all.

Frequently Asked

Are samson fish good to eat?
Mixed. Smaller fish under about 10kg are firm, white and similar to kingfish if bled and iced straight away. Bigger samsons are more likely to carry a flesh parasite that makes them unpleasant or inedible — one reason the deepwater fishery runs mostly catch-and-release.

How big do samson fish get in WA?
Commonly 5–15kg, with the Rottnest fishery producing fish over 25kg and the occasional one past 50kg. A 7.3kg tagged fish was recorded growing to about 25kg over six years.

What’s the difference between a samson fish and a yellowtail kingfish?
Both are Seriola and look alike, but samsons (Seriola hippos) are deeper-bodied with a blunter head, while yellowtail kingfish (Seriola lalandi) are sleeker with a yellow tail and a yellow flank stripe. Amberjack are the third lookalike. All three share the same WA rules.

What jig weight do you use for samson fish off Rottnest?
Knife jigs from 115g to 400g. In the deeper marks around 100m, go heavier — 250–400g — to stay in the strike zone, with some luminescence on the jig.

Do I need a licence?
Not for shore fishing, but the deepwater samson fishery is boat-based and boat fishing in WA needs a Recreational Fishing from Boat Licence. The 600mm minimum and the bag limit of 3 large pelagic finfish per day apply regardless.

When is the best time?
Year-round on deep structure, but the Rottnest spawning aggregations peak November to February. Fish the tide changes early or late in the day, around the new moon.

Samson fish are the fight WA anglers go looking for when they want to know whether their gear — or their forearms — are up to it. See the full samson fish species guide for rigs and handling, check your conditions on BiteCompass before the run across to Rotto, and bring more drag than you think you need.