The term “AJ fish” is a common abbreviation used by anglers and seafood markets to refer to the Amberjack, scientifically known as the Greater Amberjack (Seriola dumerili). This large marine predator belongs to the Jack family (Carangidae) and is the largest species within the Seriola genus. Found widely in temperate, subtropical, and tropical seas, the Greater Amberjack is highly valued globally by both recreational fishermen and commercial operations for its high-quality meat.
Physical Characteristics and Species Diversity
The Greater Amberjack has a sleek, torpedo-like body built for speed. Adults typically have a brownish or bluish-gray back with silvery-white sides, sometimes featuring an amber or pinkish hue. A defining feature is the dark, sooty stripe, known as the nuchal bar, which extends from the snout, through the eye, and reaches the front of the first dorsal fin. Unlike many fish in the Jack family, the Greater Amberjack lacks finlets and scutes.
These powerful fish commonly weigh between 20 and 40 pounds but can reach lengths of up to six feet and weights exceeding 100 pounds. The Greater Amberjack is often confused with smaller relatives, the Lesser Amberjack (Seriola fasciata) and the Banded Rudderfish (Seriola zonata). Differentiation relies on the nuchal bar, which in the Greater Amberjack extends over the eye and past the pupil. Lesser Amberjack also have proportionately larger eyes and a slightly deeper body profile.
Habitat, Diet, and Behavior
Greater Amberjack inhabit tropical and subtropical waters worldwide, including the western Atlantic Ocean, Gulf of Mexico, and Caribbean Sea. They are a demersal species, primarily living near the sea floor in offshore waters. Preferred habitats include deep-water reefs, wrecks, oil rigs, and rocky outcrops, typically at depths ranging from 60 to over 240 feet.
As opportunistic and voracious predators, adult Amberjack occupy a high position in the marine food web. Their diet consists mainly of smaller fishes, cephalopods like squid, and various crustaceans. They hunt using their speed and size to ambush prey, either in small schools or as solitary individuals. Anglers highly seek them out for their aggressive fighting style, earning them the nickname “reef donkey” due to their stubborn resistance when hooked. Their power demands heavy tackle and tests the endurance of experienced fishermen.
Culinary and Safety Considerations
The Amberjack is valued commercially for its firm, white flesh, which offers a mild-to-moderate flavor. The versatile, high-quality meat can be prepared using various cooking methods, including grilling, broiling, and baking. It is also highly regarded for raw preparations, such as sushi and sashimi, especially when sourced from farmed or smaller wild-caught fish.
However, consuming Amberjack carries a known public health risk: Ciguatera Fish Poisoning (CFP). This illness is caused by ciguatoxins, produced by dinoflagellates on tropical reef algae. The toxins bio-accumulate up the food chain, meaning larger, older Amberjack can harbor unsafe concentrations. A significant concern is that ciguatoxin is odorless, tasteless, and heat-stable, so cooking does not eliminate the danger. Symptoms of CFP include gastrointestinal issues and neurological effects, such as the characteristic reversal of hot and cold sensations. Consumers should exercise caution, particularly when sourcing larger fish from known tropical or subtropical CFP-endemic areas, and follow local health advisories.