How to Identify Black Trevally

To identify Black Trevally (Carangoides gymnostethus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults are generally silvery-grey to dark grey or black dorsally, fading to silvery-white ventrally. Fins are often dusky to black. Juveniles may have faint vertical bands. A distinctive black spot is often present on the upper operculum.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Naked (scaleless) breast region, extending diagonally to the pectoral fin base and laterally to the origin of the pelvic fins., Strongly curved lateral line anteriorly, becoming straight posteriorly., Large, robust body., Strongly forked caudal fin., Adipose eyelid well developed, covering most of eye except for a central slit.

Dorsal fin

Two dorsal fins; the first with 8 spines, the second with 1 spine and 19-22 soft rays. The anterior rays of the second dorsal fin are elongated.

Tail fin

Deeply forked caudal fin with long, pointed lobes.

Pectoral fin

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

Distinctive fins

Anal fin with 2 detached spines followed by 1 spine and 16-18 soft rays. Pelvic fins are relatively short.

Identification Tips

1. 1

   Naked Breast

   The most distinguishing feature is the scaleless area on the breast, which extends diagonally to the pectoral fin base and laterally to the pelvic fin origin. This is a key differentiator from many other Carangoides species.

2. 2

   Coloration

   Adults are typically dark grey to black dorsally, fading to silvery-white. The presence of a dark opercular spot is also a good indicator.

3. 3

   Body Shape

   Robust, compressed body with a relatively steep dorsal profile of the head.

4. 4

   Fin Morphology

   Long, falcate pectoral fins and a deeply forked caudal fin are characteristic of trevallies, but the specific ray counts and the elongated anterior rays of the second dorsal fin can aid identification.

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