How to Identify Barred Jack

To identify Barred Jack (Seriolicthys motomekiya), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Dorsal surface typically dark blue to greenish-blue, fading to silvery-white on the flanks and belly. Juveniles and sub-adults exhibit 5-7 prominent dark vertical bars on their sides, which may fade or become less distinct with age, especially in larger adults. Fins are often dusky or yellowish.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Robust, fusiform body, tapering towards the caudal peduncle., Large, deeply forked caudal fin., Prominent lateral line with a distinct arch over the pectoral fin., 5-7 dark vertical bars on the flanks, more pronounced in younger individuals., Relatively small, cycloid scales.

Dorsal fin

Two dorsal fins; the first with 7-8 spines, the second with 1 spine and 20-24 soft rays. The anterior rays of the second dorsal fin are elongated, forming a distinct lobe.

Tail fin

Deeply forked and powerful, indicative of a fast-swimming pelagic species.

Pectoral fin

Long and falcate (sickle-shaped), extending beyond the origin of the second dorsal fin.

Distinctive fins

Anal fin similar in shape to the second dorsal fin, with 2 detached spines followed by 1 spine and 15-18 soft rays. Pelvic fins are relatively small.

Identification Tips

1. 1

   Body Shape

   Look for the torpedo-shaped, robust body, characteristic of fast-swimming predators.

2. 2

   Coloration and Barring

   Observe the dark blue to greenish-blue dorsal coloration and the silvery flanks. Crucially, identify the 5-7 dark vertical bars, especially clear in smaller specimens.

3. 3

   Fin Morphology

   Note the deeply forked caudal fin and the long, falcate pectoral fins. The anterior lobe of the second dorsal fin is also a key feature.

4. 4

   Lateral Line

   Examine the lateral line, which has a distinct, high arch over the pectoral fin, then drops to run straight along the caudal peduncle.

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