Saltwater · Summer to autumn offshore and around island rocks

Spotted Mackerel

Scomber australasicus

Japan's second mackerel, caught mixed together with Pacific mackerel from boats and island rocks — and notoriously hard to separate at a glance. The teaching point is simple: lift the fish and look at the belly. A row of dark spots along the lower flanks and belly means spotted mackerel; a clean white belly means Pacific mackerel.

Seasons · Peak

Jan

Feb

Mar

Apr

May

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Spotted Mackerel — Photo: The U.S. Food and Drug Administration, Public domain — Wikimedia Commons

Identifying features

Slender mackerel body with a green, dark-marbled back
A row of dark spots along the lower flank and belly — the key mark
Pacific mackerel, by contrast, has a clean, unspotted white belly
Small scales and a deeply forked tail
Slightly slimmer and smaller-headed than Pacific mackerel

Habits

Schools offshore, often mixed with Pacific mackerel in the same school
Migrates with warm currents, moving north in summer
Feeds on small fish, krill and plankton
Comes within range of island rock anglers in summer and autumn
Strong, fast fighter on light tackle for its size

Distribution

Regional coverage expanding

Where to find them

Rock fishing (iso) on the Izu Islands, including Hachijojima
Goto Islands rocks and offshore boats, Nagasaki
East China Sea offshore fishing boats

Where they live

Offshore schools over shelf water and current linesAround remote island rocks and reefs (iso)Mixed schools with Pacific mackerel

How to catch them

Boat sabiki and jigging over schools Boat

Rig: Boat rod working a sabiki rig or small metal jig at the depth of the marked school, with krill chum to hold the fish

Bait/lure: Sabiki rig or small metal jig; krill chum

Key tip: Check the belly of every fish — mixed schools are normal, and spots mean this species.

Island rock float fishing Rock fishing

Rig: Rock (iso) rod with a float rig and krill bait cast from island rocks into the current, fished at mid-depth where mackerel run

Bait/lure: Krill pieces with krill groundbait

Key tip: Keep a steady trickle of groundbait going; mackerel follow the chum line to the hook.

Best baits & lures

Krill blocks and pieces for chum and hooksSabiki rigsSmall metal jigs

Techniques for Spotted Mackerel →

Baseline setup

Rod: Medium boat rod or 12-15 ft (3.6-4.5 m) iso rock rod
Line: 16-25 lb braid or mono with a fluorocarbon leader
Terminal: Sabiki rigs, small metal jigs, float rigs, krill chum

Recommended gear for this species

Rod · Best value

9' 5-weight fly rod outfit

≈ US$180-260

Covers chironomid lakes and small rivers with one setup.

Flies · Budget

Chironomid assortment (30 patterns)

≈ US$25-40

Chironomids are 60% of a lake rainbow's diet in spring.

Picks come from our rule library — never paid placements. Prices are guides; affiliate links may earn us a commission.

Typical size

Common 12-16 in (30-40 cm); large fish to about 20 in (51 cm)

On the table

Good — slightly softer than Pacific mackerel; grilled, or simmered in miso (saba no miso-ni).

Similar species

Pacific MackerelPacific mackerel has a clean white, unspotted belly; spotted mackerel carries a clear row of dark spots along the lower flank and belly

Regulations vary by area and can change in-season — always check the official rules for your area before you fish. Regulations guide →

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