| Ecological Descriptors
Elongate, laterally compressed; snout shorter than rest of head. Back iridescent blue-green. Adults lack spots (young may have yellow spots like Spanish Mackerel, S. maculatus). Front of dorsal fin same color as rest of fin, not black. Lateral line drops abruptly below second dorsal fin.
This species is reef-associated and oceanodromous and is often found in outer reef areas. Depth ranges from 5-140m (20-450ft. It feeds primarily on fishes, in particularly clupeids with smaller quantities of penaeid shrimps and squids. It occurs singly or in small groups often in outer reef areas. Large schools have been found to migrate over considerable distances.
Spawning is from May to September.
Ovaries show five stages of development. The ovaries of stage 5 are very mature and known when the females are about 4 years old. Sexual maturity of males is around 3 years old and at a length of about 70cm. Females between 45-150cm long release from 69,000-12,200,000 eggs. Eggs and sperm are shed into the sea, meeting by chance. The eggs hatch in approximately 24 hrs. The newly hatched larva is about 2.5mm long with a large yolk sac, in waters of temperature ranging from 26-31°C. Larvae grow up to 0.5-1.25mm daily. This short larval stage lessens the vulnerability of the larva, and is linked to high metabolism associated with this species. Larvae remain in high salinity waters throughout development. Larvae may be present across the continental shelf, but are often most abundant in middle to outer shelf waters.
Lives for up to 32 years for females and 26 for males. Average generation length has been estimated at 9 years.