Almaco Jack

Overview

The Almaco Jack (Seriola rivoliana) is a powerful, circumglobally distributed predator found in tropical and warm temperate marine waters. Often associated with deep-water structures like offshore banks and outer reef slopes, this species is frequently encountered by divers and anglers in small groups or as solitary individuals.

Distribution & habitat

This species has a wide, circumtropical range across the Atlantic, Pacific, and Indian Oceans, typically inhabiting latitudes between 43°N and 38°S. While adults are benthopelagic and often found near deep reefs, wrecks, and high-relief structures, juveniles are known to associate with floating algae, such as Sargassum, in shallower waters.

Appearance

The Almaco Jack features a deep, laterally compressed body that is more compact than its close relative, the Greater Amberjack. It is distinguished by its elongated, sickle-shaped dorsal and anal fins, with the dorsal lobe being significantly longer than the pectoral fins. Its coloration is generally olive to bronze or silvery blue-green above, fading to a lighter, often lavender-sheened belly. A characteristic dark, oblique band runs from the nape through the eye to the upper lip, which is often more prominent in younger individuals. Juveniles may also display six dark vertical body bars.

Biology & behavior

These fish are fast-swimming, nomadic predators that remain active both day and night. They are opportunistic carnivores, feeding on a variety of prey including smaller fish, squid, octopus, crabs, and shrimp. While they are sometimes found in schools, they are also frequently observed traveling alone or in small groups in open water or near deep-sea structures.