Saltwater · Winter-spring egg-bearing fish prized; caught year-round on sand-mud

Marbled Sole

Pseudopleuronectes yokohamae

The marbled sole is the real-world mainstay of Japan's 'karei' catch — a small-mouthed sole of sand and mud taken by boat fishing and surf casting with worm baits. Egg-bearing fish in winter and spring are especially prized. It contrasts with the stone flounder, which carries bony plates, and with the big, predatory-mouthed olive flounder.

Seasons · Peak

Jan

Feb

Mar

Apr

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Dec

Marbled Sole — Photo: Utan506, CC BY-SA 4.0 — Wikimedia Commons

Identifying features

Both eyes on the right side; eyed side brown with marbled darker patches
Very small mouth, unsuited to lures or fish baits
Smooth, slimy skin and a rounded, soft body outline
Blind side white, sometimes with a yellowish tinge
No bony plates or bars — pattern is marbling, not stripes

Habits

Feeds on marine worms, small shellfish and crustaceans in sand-mud
Egg-bearing fish gather inshore in winter and spring
Buries itself shallowly in sand or mud by day
Moves onto feeding grounds with the tide
Taken in numbers by worm baits fished hard on the bottom

Distribution

Regional coverage expanding

Where to find them

Tokyo Bay sand-mud boat grounds
Sendai Bay surf and boat karei grounds
Seto Inland Sea bay sand-mud flats

Where they live

Sand and mud bottoms of bays and inshore seas in 15-130 ft (5-40 m)Surf edges and harbour mouths over clean sandEstuary mouths where sand meets mud on a falling tide

How to catch them

Boat fishing over bay sand-mud Boat

Rig: Two or three-hook karei rig with a 2-4 oz sinker, fished static on sand-mud

Bait/lure: Marine worms

Key tip: Anchor over bay sand-mud and wait; small, rattling bites are typical, so give them a moment before lifting.

Surf casting for karei Shore

Rig: Casting rig with two hooks above the sinker, thrown from sandy beaches and harbour mouths

Bait/lure: Marine worms or clam pieces

Key tip: Cast to clean sand, retrieve in short pulls with pauses, and keep the bait on the bottom.

Best baits & lures

Marine worms (isome)Clam piecesSmall shrimp pieces

Techniques for Marbled Sole →

Baseline setup

Rod: Light-medium 7-9 ft boat or surf rod
Line: 12-20 lb braid or mono
Terminal: Karei rigs with size 8-12 hooks, 2-4 oz sinkers

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 8-12 in (20-30 cm); large fish to about 16 in (40 cm)

On the table

Good — soft, sweet white flesh; winter-spring egg-bearing fish (komochi) are a seasonal delicacy in Japan.

Similar species

Stone FlounderStone flounder has an unmistakable row of bony plates along the lateral line; marbled sole is smooth-skinned with marbled patches and no plates

Olive FlounderOlive flounder is a large left-eyed predator with a big toothed mouth that takes lures; marbled sole is a small right-eyed, small-mouthed worm-eater

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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