The cleftbelly trevally (Atropus atropos), also known as the cleftbelly kingfish, Kuweh trevally or thin crevalle, is a species of tropical marine fish of the jack family, Carangidae.

DESCRIPTION

·        The cleftbelly trevally has a body shape similar in many ways to a number of the larger jacks, with a strongly compressed body almost ovate in shape.

·        The dorsal profile of the head is straight and steep from the tip of the upper jaw to above the eye where the profile becomes convex.

·        The eye lacks an adipose eyelid, and the upper jaw has a narrow band of small teeth, while the lower jaw has two or three rows of small teeth which narrow to one row on the sides of the jaw.

·        The ventral profile is concave upwards, with a major distinguishing feature of the species being a deep median groove along the belly, into which the large pelvic fins fold, also encompassing the first two anal fin spines and anus.

·        The entire chest from underneath the pectoral fins to the base of the pelvic fins is scaleless.

·        There are two separate dorsal fins, the first with eight spines and the second with a single spine followed by 19 to 22 soft rays.

·        The anal fin has two detached spines before the major part of the anal fin, which consists of one spine and 17 or 18 soft rays. The pectoral and pelvic fins are both quite long, with the latter extending almost to the anal fin origin.

·        The lateral line has a moderately strong arch anteriorally which intersects the straight section underneath the fifth to seventh dorsal rays. The straight part of the lateral line has 31–37 scutes.

·        There are 24 vertebrae and 29 to 34 total gill rakers.

·        The species is known to reach 26.5 cm in length, although often encountered below 20 cm.

·        The cleftbelly trevally is a bluish green on the upper body which fades to silver on the underside of the fish.

·        The membranes of the large pelvic fin are a distinctive black, while the remaining fins are a pale white colour. Juveniles have indistinct dark bands across their bodies, with a black spot becoming more prominent in adults.

·        The species show sexual dimorphism in their dorsal fins, with mature males having between 6 and 12 elongated soft rays, strung out into filaments of varying lengths.

·        The anal fin is also has five similar extensions of the soft rays. Females do not show this elongation.

DISTRIBUTION AND HABITAT

·        The cleftbelly trevally inhabits the tropical and subtropical waters of the Indo-West Pacific region. Its range extends from South Africa along the east African coast including the Persian Gulf, east to India, Southeast Asia, the Philippines, Taiwan and southern Japan.

·        The species inhabit shallow coastal waters, where they swim close to the surface. There has been a report of the species living in areas near estuaries which empty large flows of fresh

DIET

·        The cleftbelly trevally is a predatory species, preying on small crustaceans including shrimps, copepods and decapods, as well as small fish.

 REPRODUCTION

•      The studies showed the fish grows 12.4 cm in its first year of life, growing slower in its second and third years, adding 7.35 cm and 3.5 cm to its total length, respectively, in these years.

•       The species reaches sexual maturity at 21 cm, in the second or third year of its life.

•        The species is of minor importance to fisheries throughout its range, taken mainly by trawls, traps and by various hook-and-line methods.