How to Identify Korean Sole

To identify Korean Sole (Heteromycteris japonica), look at these key features.

Physical Characteristics

Body shape

flat

Coloration

Dorsal side is typically mottled brown, grey, or yellowish-brown with irregular darker spots and blotches, providing excellent camouflage against sandy or muddy bottoms. The ventral side is whitish. The fins often have faint banding or spotting.

Scale type

ctenoid

Mouth position

inferior

Distinctive features

Dextral (right-eyed) flatfish, meaning both eyes are on the right side of the head., Small, asymmetrical mouth, with the upper jaw slightly longer than the lower jaw., Anterior nostril of the blind side is tubular and elongated, extending beyond the mouth., Lateral line present on both sides, but more prominent on the eyed side, with a distinct arch over the pectoral fin.

Dorsal fin

Originates anterior to the eye, extending almost the entire length of the body, with 60-70 soft rays. Not confluent with the caudal fin.

Tail fin

Rounded or slightly truncate, with 12-14 rays. Separate from dorsal and anal fins.

Pectoral fin

Small and rudimentary or absent on the blind side; present and small on the eyed side, with 4-6 rays.

Distinctive fins

Anal fin with 45-55 soft rays, extending along the ventral margin of the body. Pelvic fins are small, asymmetrical, and located anterior to the anal fin.

Identification Tips

1. 1

   Eye Position

   Always check for both eyes being on the right side of the head (dextral).

2. 2

   Nostril Shape

   The elongated, tubular anterior nostril on the blind side is a key diagnostic feature.

3. 3

   Body Shape and Coloration

   Its oval, flattened body and mottled brown/grey coloration are typical of sole species, but the specific pattern can help differentiate it.

4. 4

   Fin Separation

   The dorsal, anal, and caudal fins are distinctly separate, not confluent.

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