Latin name

Trachinotus botla

Other name

Trachinotus botla

Identification

The body of the large spotted dart is elongated, oval in shape, strongly compressed at the sides and covered with fine cycloid scales. The upper and lower body profiles are convex and similar in shape. The upper profile of the head is hollow and sloping towards the rounded snout. The eyes are small, their diameter is 3.4-4.1 times the length of the head. The tip of the upper jaw extends to a vertical line passing through the centre of the eye. The teeth on both jaws are small, tufted and arranged in strips. On the scutellum the teeth are arranged in a patch of oval or triangular shape. The fangs on the palate are short. There are no teeth on the tongue. There are 6-9 gill stamens on the upper part of the first gill arch and 11-15 stamens on the lower part. The lateral line forms a low arch above the pectoral fins. Vertebrae: 10 dorsal and 14 caudal vertebrae.

Features of fish fins

Dorsal spines (total): 7; Dorsal soft rays (total): 22 - 24; Anal spines: 3; Anal soft rays: 19 - 22.

The first dorsal fin has 6 separate short barbs. The second dorsal fin has one hard and 22-24 soft rays. The anal fin has one barbed and 19-21 soft rays. There are 2 short barbels in front of the fin. The anterior lobes of the second dorsal and anal fins are long. The pelvic fins are relatively long, 1.5-1.7 times the length of the pectoral fins. There are no grooves or keels on the caudal peduncle. The caudal fin is deeply divided. 

Fish colouring

The upper part of the body is bluish black, the sides and belly are silvery. There are 3-6 large oval spots on the sides of the body (there are no spots on individuals less than 15 cm long). The number of spots increases as the fish grows. The number, location and intensity of the spots vary between individuals of the same size. Only one of the anterior spots is above the pectoral fins. The spots touch or extend only slightly below the lateral line. The spots are larger than the diameter of the eye and are silvery grey in colour when the fish is alive. The second dorsal and anal fins are bluish black with darker edges. Caudal fin dark, upper parts of blades bluish black. Pectoral fins pale, sometimes with black upper part. Pelvic fins are white.

Distribution

Widespread in the Indian Ocean: Somalia and Kenya to Algoa Bay, South Africa; also Madagascar, Sri Lanka and Western Australia.

Habitat

A tropical marine benthopelagic, reef-associated species that prefers brackish waters.

Size

Maximum length of males is 75 cm. Total length of males - 60 cm. Maximum recorded weight - 2.3 kg. It is a fast growing fish, in 2 months individuals can reach a length of 132 mm. 

Behavior

The only members of the family that spend their entire life cycle in coastal waters. They live in the surf zone; juveniles are found in the shallowest areas, sometimes ending up on the sand after the wave has receded; adults move to deeper parts of the zone. 

Food and feeding habits

The diet of juveniles consists mainly of copepods, terrestrial insects, small fish and Emerita. Adults feed on mussels, crabs, fish (mainly anchovies) and snails. 

Reproduction

Males reach sexual maturity (50% of the population) at an average body length of 25.2 cm, and females at 24.2 cm; at the age of 2.3 years. They spawn off the coast of South Africa from November to February. Life expectancy does not exceed 6-7 years.

Fishing

The large-spotted darter has little commercial interest in the fishery.

Relationship with a person

Harmless.