The blacktip trevally (Caranx heberi), also known as the blacktip kingfish or yellowtail kingfish, is a species of large marine fish classified in the jack family Carangidae.

DISTRIBUTION AND HABITAT

• The blacktip trevally is distributed throughout the tropical and subtropical waters of the Indian and West Pacific Oceans.

• In the western part of its range, the species ranges from South Africa and Madagascar north along the east African coast up to the Persian Gulf and Red Sea.

•  Its distribution continues eastward through India, South East Asia and the Indonesian Archipelago. Its range extends south to northern Australia, north to Japan and to Fiji in the east.

• The blacktip trevally is predominantly an inshore species, frequenting clean open coastal waters as an adult, with juveniles also found in large bays and estuaries.

• Adults are often found over moderately deep rocky reefs and pinnacles as well as open sandy areas.

DESCRIPTION

• The yellow fins and black caudal fin tip are characteristic of the species

• The blacktip trevally is a large fish, growing to a maximum recorded size of 1 m in length and 12.5 kg in weight.

•  It is similar to most other jacks in having a compressed, oblong body, with the dorsal profile much more convex than the ventral profile, particularly anteriorly.

• The dorsal fin is in two distinct sections; the first consisting of 8 spine and the second of 1 spine and 19 to 21 soft rays.

• The anal fin consists of 2 anteriorly detached spines followed by 1 spine and 15 to 17 soft rays.

• The ventral fin consists of 1 spine and 5 soft rays, while the caudal fin is strongly forked.

• The species lateral line is moderately arched anteriorly, with 50 to 60 scales in this section, while the straight section contains 0 to 4 scales and 30 to 40 strong scutes.

• The pattern of breast scales is variable, ranging from fully scaled to naked ventrally.

• The species has moderately well developed adipose eyelids, while its dentition consists of an outer row of widely spaced canines and an inner band of villiform teeth in the upper jaw and a row of widely spaced conical teeth on the lower jaw.

• The blacktip trevally has 24 to 27 gill rakers and 24 vertebrae.

• The blacktip trevally's colouration is distinctive, with the upper body being dark bronze to yellow green while the lower body fades to silvery white below.

• The caudal fin is bright to olive yellow, with the top half normally black to dark, giving the species its common name.

• Other fins range from bright yellow to dusky with little yellow at all.

•  The species also lacks the dark spot on the opercular margin that many related species possess.

HABITAT AND BEHAVIOR

• The blacktip trevally travels in both small shoals and individually throughout its habitat, with juveniles more commonly found in shoals.

•  They appear to be migratory, with South Africa recording influxes of the species in summer, while in India they arrive after the monsoons and continue their inhabitance through the cold months.

• The species is a benthopelagic predator, taking its prey from the sea floor and higher in the water column. Prey items include a variety of fish, cephalopods, and crustaceans including shrimps, mantis shrimps, crabs and crayfish.

• Little is known about the reproduction of blacktip trevally, but it's believed that spawning takes place in more tropical regions of their range. Some say they are batch spawners that scatter their eggs in open water or on the substratum without guarding them. During spawning, females release thousands of eggs into the water, where they are fertilized by sperm from males. The drifting forms eventually settle out as juveniles, which may move into shallow inshore waters and then out to deeper reefs as they grow.

RELATIONSHIP WITH HUMANS

• The blacktip trevally is of minor importance to commercial fisheries throughout its range, taken by hook and line and various netting methods, from where it is sold fresh, salted or dried at market.

•  The species is considered a good gamefish and can be taken by fish or squid baits as well as various patterns of lure and fly.

• When taken from the water, the fish often 'grunt' in similar manner to a young pig.

• They are considered an excellent table fish despite being known to be a host to parasitic infection in some regions.