In this article two fish are described, both fairly common in UAE waters; Decapterus russellii and Gnathanodon speciosus. These fish are from the family Carangidae (commonly known as "Trevally") and are fast swimming surface predators of moderate size. They usually run in large schools in the vicinity of coral reefs.Decapterus Russellii
D. Russellii is known commonly as mackerel or scad and in Arabic as 'sima' or 'baleg'. It is regarded by some as a game fish.Description
Body outline as in sketch. Body colouring is blue-green above with a silvery belly. Scales are very small and inconspicuous. The eyes are large and there is a black spot on the opercle. All the fins have a yellowish tint. D. russellii grows to a length of 45 cms.Habits and Habitat
This fish is usually found in schools feeding around corals and rocks. Though by nature an offshore pelagic species, adults come closer inshore to breed. The young move offshore - presumably to feed on plankton - and return to the inshore areas in large schools when about 12 cms. in length.
G. speciosus is a beautiful fish with vivid markings, and is commonly known as the Golden Trevally.Description
Shape as in sketch. The body is compressed and has a silvery background colour speckled with yellowy-bronze. There are five distinct vertical marks interspersed with lesser marks on the body plus a clear mark passing through the eye. The head is darker in colour. Fins are tinted bronze with black flashes on the caudal fin. The lateral line is pronounced. Body colouring tends to fade with age.Habits and Habitat
G. speciosus can usually be found around coral reef areas, and is often seen in small schools searching for food. The species has been sighted swimming around the legs of offshore wellheads and platforms.