- Although the flesh of the almaco jack is considered quality table fare, the species has been associated with ciguatera poisoning, a seldom fatal stomach irritation.
- The almaco jack is susceptible to tapeworm parasites in the caudal peduncle area, but the meat can be eaten safely if affected portions are cut away.
The common dolphinfish, or “dolphin,” is of no relation to the member of the porpoise family of mammals that carries the common name. The body of the dolphinfish is quite slender but fairly deep, with a noticeable tapering from head to tail. The male of the species is distinguished from the female by its high, vertical head. The anal fin has approximately 30 soft rays and stretches over half of the length of the body. The distinctive dorsal fin is long, covering almost three-fourths of the body, and has around 60 soft rays. The caudal fin is deeply forked and contains no spines.
Coloring, in general, is an iridescent blue or green in the dorsal area, a bluish or silvery gold on the lower flanks and a silvery white or yellow on the belly. The sides are dotted with dark and light spots, ranging from black or blue to golden. Dolphinfish frequently use their bright coloring to signal others in the school. For example, silver is a warning of impending danger.
Dolphinfish are known as voracious predators. While their favorite prey is the flying fish, they also consume squid, shrimp, crustaceans and even smaller dolphinfish. Using a keen sense of eyesight the dolphinfish locates most food near clumps of floating vegetation and objects. They tend to feed in pairs, small packs and schools. They are considered to be non-selective foragers, with the male taking proportionally more of the active, fast-swimming species than the female. Because they feed by sight, they are primarily daylight foragers.
While the greatest concentrations of dolphinfish are believed to be in the Indian Ocean and the western Pacific, they are found worldwide in tropical and subtropical waters and warmwater currents. In the western Atlantic, they are seen as far north as Prince Edward Island and as far south as northern Brazil; from the Canary Islands to Angola in the east Atlantic; and from Oregon to Peru in the eastern Pacific.
Dolphinfish are a warm-water fish usually found in deep waters, close to the surface. While sometimes found in coastal waters, they often concentrate in the open ocean around floating objects such as buoys, driftwood and seaweed clusters. They are considered to be the most surface-oriented of all big-game fish. The younger fish are more prevalent in the warmer, near-shore waters in sargassum beds or other flotsam. Dolphinfish are migratory, with fish in both hemispheres moving away from the equator in spring and summer and toward the equator in fall and winter as the fish seek waters in the 70 to 75 F range.
It is common for dolphinfish to travel in very large schools and they have the ability to swim at speeds as high as 50 miles per hour.
- Dolphinfish are prized because of their firm meat and delicate flavor. Annual harvests of the fish are estimated at 30,000 to 40,000 tons.
- Because of its durability, dried dolphinfish skin is sometimes used to make trolling lure skirts.
- The name dolphinfish does not imply a resemblance to the marine mammal.
Rather, the name was applied to dolphinfish because they have a tendency to follow boats in the wake of their bow like dolphins do.
- While they are almost at the top of the food web, dolphinfish are preyed upon by some larger species, including tuna and marlin.