- 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.
Atlantic sailfish (Istiophorus)
Atlantic sailfish are members of the billfish family and are related to the larger marlin. They are so closely related to the Pacific sailfish that there is still debate about whether they are the same species. Atlantic sailfish appear to grow to only about one half the size of Pacific specimens, though recent information suggests they can grow larger than previously recognized.
The Atlantic sailfishs most prominent feature is their first, sail-like dorsal fin, commonly referred to as its sail dorsal. The sail dorsal is high and long, having between 37 and 49 rays. It is steel blue with light and dark blue spots. Coloration of the body is dark blue to dark blue-green on top, brown-blue on the sides fading to silver-white underneath. The upper body has light and dark blue spots scattered about, while the sides have blue-gray vertical stripes that are often broken.
The body of an Atlantic sailfish is slender and they are extremely fast swimmers, having the ability to swim at speeds up to 60 miles per hour. There is an obvious lateral line that runs over the pectoral fin and back along the flanks. The body is covered with embedded scales that become less numerous and more variable in shape as the fish ages. The long upper jaw is shaped like a spear and is longer than that of a spearfish. The lower jaw is less than one-half the length of the upper.
There is a second dorsal fin that is much smaller than the first and has only 6 to 8 rays. The pectoral fins can be folded to become flush with the body. The pelvic fins are narrow and extend to the anal fin and have a single spine with several rays fused together. The pelvic fins can also be folded into a groove against the body. The anal fins have 9 to 12 rays. They can be distinguished from marlin by the difference in the sail fin, which reaches its highest point much closer to the head on marlin.
Feeding primarily at mid-level depths, Atlantic sailfish make only occasional trips to the surface. Favored feeding areas are near schools of baitfish in areas where there is a temperature change. They may form small groups of 3 to 30 members that forage together. It is possible that, like the Pacific sailfish, they may cooperate to capture their prey, using their fins to create a trap that prevents fish from escaping and taking turns to feed. They attack prey with their fins and spear and then consume the stunned fish headfirst. Their favored food is other fish, including mackerel, tuna, herring, ballyhoo, needlefish and mullet. They also enjoy squid and octopus.
Atlantic sailfish migrate extensively throughout the tropical and temperate waters of the Atlantic Ocean. The full range is from about 40 degrees north to 40 degrees south latitude in the western Atlantic, roughly from Maine to Venezuela. They are found throughout the Gulf of Mexico and Caribbean. In the eastern Atlantic, they range from about 50 degrees north to 32 degrees south, from England south to the Mediterranean Sea and along the coast of Africa.
Although they traverse the vast ocean waters, Atlantic sailfish favor areas near the Gulf Stream current. They stay at mid-range to surface depths above the thermocline, in waters with temperatures between 70 and 85 F. Despite being caught on the surface, most of their feeding appears to occur in mid-level depths near areas with underwater structures. Compared to their Pacific counterpart, they usually stay in deeper water year round, going to depths as great as 600 feet.
Atlantic sailfish congregate in warm current waters just offshore from the continents out to the edge of the continental shelf or over oceanic mountains. They appear to school by size while foraging on schools of ballyhoo, squid and mullet. Their migrations are directly linked to changes in water temperature. On the Atlantic coast of the United States they will migrate north in April and May and return to southern waters in September and October. These migrations are so closely associated with temperature that arrival of Atlantic sailfish in a particular location can be anticipated with a high degree of accuracy.
- There are growing concerns about Atlantic sailfish population because of increased commercial and pleasure fishing, especially by the Japanese in the Caribbean. Others site the short life span of the Atlantic sailfish as evidence that the species can quickly regenerate its population, making it less susceptible to overfishing concerns.