- 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.
Pacific sailfish (Istiophorus)
The Pacific sailfish is a small member of the billfish family and is related to the larger marlin. It is so closely related to the Atlantic sailfish that there is still debate about whether they are a single species. With its distinctive large, colorful, sail-like dorsal fin, its ability to make impressive leaps out of the water, and its amazing speed, it one of the most recognized member of the billfish.
Pacific sailfish are dark blue to dark blue-green on top, though when excited they become brighter, attaining a color some call electric blue. The sides are brown-blue fading to silver-white on the belly. The primary color of the sail dorsal is steel blue. The upper body and the main dorsal fin are sprinkled with light and dark blue spots. The sides often have powder blue or blue-gray vertical stripes. Many Pacific sailfish have a gold or copper tint to the gill covers, especially when fatigued. The base of the anal fins usually has a silver-white hue.
The body of a Pacific sailfish is slender with a noticeable lateral line that runs over the pectoral fin and back along the flanks. The body is covered with embedded scales that become more sparse and variable in shape as the fish grows. They have 24 vertebrae with 12 each in the pre-caudal and caudal sections of the body. The upper jaw is very long and shaped like a spear, while the lower jaw is only one-half as long. Pacific sailfish have small, file-like teeth.
There are two dorsal fins on a Pacific sailfish. The first, the recognizable sail fin, has between 37 and 49 rays and is generally taller than the rest of the body. The second dorsal fin is considerably smaller and has only 6 to 8 rays. The pectoral fins have 18 to 20 rays and can be folded to become flush with the body. The pelvic fins are narrow and extend to the anal fin. They 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 12 to 17 and 6 to 7 rays respectively. The caudal peduncle has double keels on each side and a shallow notch on both the top and bottom surfaces.
Pacific sailfish can be distinguished from the Atlantic sailfish by the much brighter color of its body. They can be differentiated from marlin by the difference in the sail fin, which reaches its highest point much closer to the head on marlin.
As noted, Pacific sailfish feed primarily at mid-level depths with occasional forays to the surface. Their favored feeding grounds are near schools of baitfish in areas where there is a temperature change, usually near the major ocean currents. They sometimes travel in schools of 3 to 30 members, especially in winter. When necessary, they will cooperate to capture their target and take turns feeding. In many cases, they will strike their prey with their fins and then consume the stunned fish head first.
Pacific sailfish will eat a variety of fish, crustaceans and cephalopods. Their favored food is other fish, such as mackerel, tuna, herring, ballyhoo, needlefish, mullet and, when necessary, sardines and anchovies. They also eat squid and octopus.
This species migrates widely throughout the tropical and temperate waters of the Pacific Ocean, Indian Ocean and Mediterranean Sea. The full extent of the Pacific sailfishs range is from about 50 degrees north to 40 degrees south latitude in the western Pacific, from about 35 degrees north to about 35 degrees south in the eastern Pacific and to 35 to 45 degrees south in the Indian Ocean. They occasionally come near shore in pursuit of prey, but are most often found several miles offshore.
Pacific sailfish are most prevalent from Mexico to the Hawaiian Islands to the Sea of Japan in the north Pacific, from Mexico to Peru on the east, from Peru to Tahiti, the Solomon Islands, Papua New Guinea, northern Australia and the Banda Sea on the south and from the Banda Sea to the Philippines, East China Sea and Sea of Japan on the west. They are also found in the Indian Ocean from Sri Lanka north and west to the Red Sea and into the Mediterranean Sea.
Pacific sailfish are a species that roams the vast ocean waters at mid-level and surface depths and are found above the thermocline, the level at which there is a rapid change from warm to cool water temperatures. Despite the fact that they are usually taken at the surface, most of their feeding appears to occur in mid-level depths near areas with underwater structures. They tend to congregate in warm water just offshore from the continents to the edge of the continental shelf or over oceanic mountains. Near land they will be found near warm currents with a temperature range from 70 to 85 F. They appear to school by size and seek schools of ballyhoo, squid and mullet.
- Pacific sailfish are a difficult species to study because of their wide migration and location offshore. As a result, it is difficult to tag these fish and gather data.
- Scientists base much of their sailfish research on data provided by anglers. The body of knowledge about Pacific sailfish is limited primarily to range, habitat, growth and diet.