Blue Salmon & Giant Herring: Northern WA Sportfish

Blue salmon is the everyday WA name for blue threadfin (Eleutheronema tetradactylum) — also called Cooktown salmon, or just “threadie”. A slim, silver threadfin of the tropical north, not a salmon and not related to one. It works beach gutters, sand flats and creek mouths from the Pilbara to the Kimberley, hunting prawn, mullet and small baitfish on the rising tide, usually in better numbers than its bigger cousin the king threadfin. Most run 40–70cm and top out around 90cm, with fish to around 3kg common — the metre-plus threadfin are kings, not blues. A willing biter, a clean fighter that skips across the surface — and, the part that matters, excellent on the plate. For the full threadfin family rundown, including the prized king threadfin, see the threadfin guide.

Giant herring (Elops machnata) is the local “ladyfish”, the poor man’s tarpon. Long, slim and bright silver, it schools around estuary mouths, harbour edges and sandy beaches from Shark Bay north. Most are 1–4kg, with fish to a metre and around 10kg. Hook one and it’s airborne instantly — greyhounding and tail-walking across the surface, throwing hooks the whole way. That’s the fun, because it certainly isn’t the eating.

The name needs clearing up, because the search results muddle it constantly. Blue salmon is not the Australian salmon of the south coast. Australian salmon (Arripis) is a cool-water schooling fish that runs the surf beaches around Perth and the South West, mostly in autumn. Blue salmon is a tropical threadfin of the far north. They share a word and nothing else — different family, different climate, opposite ends of the state. Warm water at a Pilbara creek mouth, it’s blue salmon; a cold South West beach in March, it’s the other one. Settlers named a lot of WA fish after things they half-remembered from home, and this is one of them.

Both are tropical and both fish best on the run-in and run-out tides around structure — creek mouths, harbour walls, sandbanks and beach gutters where the current concentrates bait. Blue salmon peak through the dry season, roughly April to November, when the beaches and creeks are most fishable; giant herring are year-round, with the cooler dry-season months (April–October) the most comfortable to fish. For both, the last hour of the run-in, the change, and the first of the run-out are prime, especially around the new and full moons. Dawn, dusk and the first hour of dark outproduce the middle of the day every time.

North-to-mid-coast, all moving-tide creek-and-beach country.

Light-tackle fishing, and the gear is the same for both with one change in lure choice. The outfit: a 7ft light-to-medium spin rod, 10–20lb braid, and a 15–25lb fluorocarbon leader. No wire — neither fish has cutting teeth, so wire is for the mackerel and barracuda you might hook up north, not these.

• Lures (both): small soft plastics on 1/4–3/8oz jigheads, and soft vibes — these cover both equally.
• Lures (blue salmon): slow-rolled paddle-tails and small suspending hardbodies, worked slowly with the current on the run-in.
• Lures (giant herring): small chrome slugs and metals, and small surface poppers or stickbaits, worked fast — a quick retrieve triggers the chase.
• Baits (blue salmon): live prawn, mullet or herring, or fresh mullet strip on a running-sinker rig with a 3/0–4/0 circle hook and 20–30lb leader, just enough lead to hold in the wash.
• Hooks: sharp single hooks on lures, barbs crushed for the giant herring you’ll be releasing.

The one technique difference is in the mouth. Blue salmon have a soft mouth that tears under heavy load, so feed line on the take and lift gently rather than striking hard. Giant herring have hard, bony mouths and shed hooks the instant the line goes slack — keep the rod tip working through every jump to stay connected.

Here’s where they split. Blue salmon is excellent — moist, white, mild flesh that’s among the better eating fish of the tropical north, and the smaller fish are arguably better than big king threadfin. Bleed and ice it on capture in the heat; it pan-fries and grills beautifully.

Giant herring is poor — bony and dry, riddled with fine intramuscular bones, and not worth keeping. Crush your barbs, keep it in the water, and put it back; it’s a delicate fish that releases best with minimal handling. Same tide, same lure: one goes in the esky, one goes back over the side.

Blue salmon is a blue threadfin, which sits under “threadfin, other species” in WA rules — no minimum size, a daily bag of 4 — within the statewide nearshore/estuarine finfish mixed daily bag of 16. King threadfin is managed separately, at a 450mm minimum and a bag of 2, so know which one you’re holding. Giant herring isn’t individually listed in the main tables and falls within the “all other species” mixed daily bag, with no minimum size — though almost everyone releases them anyway.

Regulations shift, and a screenshot from two seasons ago isn’t current. Confirm the numbers at DPIRD’s recreational bag and size limits before you head out.