Saltwater · Winter peak November-March in cold water; moderate in spring
Littlemouth Flounder
Pseudopleuronectes herzensteini
The round sand flounder of the cold east coast — 참가자미. The winter flatfish complement to marbled sole (same genus Pseudopleuronectes), recognised by its tiny mouth — hence 'littlemouth'. Boats off Gangneung and Sokcho take it over sand and gravel on tiny hooks. The Chinese name 高眼鲽 follows the Limanda synonymy in the literature.
Seasons · Peak
Identifying features
- Round flounder shape like a small marbled sole
- Eyes on the right side of the head
- Brown upper side with fine pale and dark speckles
- Small mouth — the reason for the 'littlemouth' name
- Lateral line nearly straight with a slight curve
Habits
- A cold-water flatfish of the east coast
- Lies on sand and gravel eating worms and small crustaceans
- A close relative of marbled sole — same genus
- Most active in winter when other flatfish move off
- Soft flesh — handle carefully
Distribution
Regional coverage expanding
Where to find them
- Gangneung sand, east coast
- Sokcho deep sand
- Donghae mixed ground
Where they live
How to catch them
Winter boat fishing over sand Boat
Rig: Flounder bottom rig with sandworm on tiny hooks fished from a boat over 30-100 ft east-coast sand
Bait/lure: Sandworm
Key tip: The mouth is tiny — use the smallest hook and give the fish time to take the bait fully.
Drifting over mixed ground Boat
Rig: Light bottom rig with shrimp drifted over sand-gravel transitions at Donghae
Bait/lure: Shrimp pieces
Key tip: Flounder hold the sand sides of transitions — drift along the edge, not across it.
Best baits & lures
Baseline setup
- Rod: Light 7 ft boat rod
- Line: 8-12 lb monofilament
- Terminal: Small hooks size 6-8 on a flounder bottom rig
Recommended gear for this species
Rod · Best value
7'6" medium-heavy jigging rod
≈ US$110-170
Works 2-6 oz jigs over rock and reef and still has the backbone to lift a halibut off the bottom.
Line · Budget
50 lb braid with 40 lb leader (200 yd)
≈ US$25-40
Thin braid cuts the current so jigs stay vertical; the leader shrugs off rock and teeth.
Terminal · Budget
Leadhead jigs, swimbaits and two-hook bottom rigs
≈ US$25-40
A leadhead with a swimbait tail is the universal bottom-fish catcher, from rockfish to cod to flounder.
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 about 15 in (38 cm)
On the table
Good — a valued east-coast flounder, popular as a winter fish in Korea.
Similar species
Marbled SoleMarbled sole (same genus) has dark bands across the eyes and a larger mouth; littlemouth flounder has a tiny mouth and quieter pattern
Ridged-eye FlounderRidged-eye flounder of the west coast has spots on the tail and fin edges; littlemouth flounder is a quiet sand colour of the east coastRegulations 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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