Mackerel Scad
Decapterus macarellus
    Ecological Descriptors
Habitat Size (cm) Diet Behaviour Sex 
Pel 30 (max 45) Pla Sh F
Black spot at upper edge of operculum (Round Scad can also have this spot but has large central scutes along rear third of body). Only slightly enlarged scutes at base of tail. Bright silver and long narrow body, often with a blueish or greenish sheen. Occasional yellow stripe midbody. Lateral line slightly arched. Caudal fin (tail fin) yellowish and can have dark tips, however can be reddish (similar Redtail Scad forms muchtighter shoals in general and has enlarged scutes) .Narrow caudal peduncle (characteristic of Carangidae and helps dististinguish Scads from Herrings [Clupeidae). Single dorsal and anal finlet.

Adults prefer clear oceanic waters, frequently around islands . Sometimes they are found near the surface, but generally caught between 40 and 200 m depth. Pelagic  Usually seen as fast moving schools along the reef edges, usually near deep water. They feed mainly on zooplankton.

Life Cycle:
Eggs are pelagic. The juvenile fish grow inshore, and after 2 years they are mature and form adult schools, at a size of about 26cm. Hundreds of thousands of pelagic eggs are spawned that hatch into pelagic larvae, free-floating in the open sea. The spawning period occurs from April to July.
Mackerel Scad
(C) Keoki Stender
Mackerel Scad