''Trachurus delagoa'', the African scad, is a species of

jack mackerel Jack mackerels or saurels are marine ray-finned fish in the genus ''Trachurus'' of the family Carangidae. The name of the genus derives from the Greek (language), Greek words ''trachys'' ("rough") and ''oura'' ("tail"). Some species, such as ''T ...

from the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Carangidae The Carangidae are a family of ray-finned fish that includes the jacks, pompanos, jack mackerels, runners, trevallies, and scads. It is the largest of the six families included within the order Carangiformes. Some authorities classify it as the ...

which is found in the south western Indian Ocean.

Description

''Trachurus delagoa'' has an elongate body which is slightly compressed and has the upper and lower profiles roughly the same. The eye is moderately large and has a well-developed adipose eyelid which normally covers almost all of the eye apart from a vertical oval with the pupil in the centre. It has a reasonably wide upper jaw which extends to underneath the forward anterior edge of the eye. The mouth is equipped with small teeth, having a single row in each jaw. It has two separate

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

s, the first having 8 spines with the second having a single spine and 28 to 32 soft rays. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has 2 detached spines to its front followed by a single spine and 24 to 28 soft rays. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s are as long or longer than the length of the head. The scales in the lateral line and large and form scutes. It has a black spot on the upper margin of the operculum, the upper part of the body is dark blue and the flanks and belly are silvery. The anal and pectoral fins are pale yellow in colour, the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

is grey and the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s are white or unpigmented. It grows to a maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

of .

Distribution

''Trachurus delagoa'' occurs in the south-western Indian Ocean off the eastern costa of Africa from

Eastern Cape Province The Eastern Cape ( ; ) is one of the nine provinces of South Africa. Its capital is Bhisho, and its largest city is Gqeberha (Port Elizabeth). Due to its climate and nineteenth-century towns, it is a common location for tourists. It is also kno ...

to southern Mozambique. It is also found off southern Madagascar and the

Walters Shoals The Walters Shoals is a group of submerged mountains off the coast of Madagascar. The shoals are south of Cape Sainte Marie - Madagascar and east of Richards Bay at the African coast. The tips of some of the mountains are only below the surf ...

Habitat and biology

''Trachurus delagoa'' is largely

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer o ...

and occurs in areas of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

where there is a sandy substrate. It ranges in depth from the shoreline to around . It spends the day in the depths and undertakes a vertical migration at night to feed near the surface. Its prey is made up largely of smaller fish and crustaceans. It is a social species which forms schools.

Fisheries

African scads are largely fished for with bottown trawls and with hook and line. In

KwaZulu Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

it is fished for on a small scale by fishermen on paddleboards or kayaks.

References

{{taxonbar, from=Q2272654 Trachurus delagoa Marine fish of Southern Africa Fish of Madagascar Fish described in 1970