- 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.
Blue marlin (Makaira)
The blue marlin is a highly regarded member of the billfish family and considered by many anglers to be the top big game species in the sea. The Atlantic and Pacific specimens are nearly identical in appearance. The back and upper portions of the body are dark, cobalt blue in color, including the first dorsal fin. The lower portion has a silver-white color. In many cases, there are up to 15 vertical stripes, consisting of small dots and narrow bars, with a light cobalt blue color. These stripes become quite bright when the fish is ready to strike or when hooked, but they rapidly disappear when the fish is removed from the water. The remaining blue marlin fins are generally black-brown in color and the anal fins have a bit of silver-white tinge. None of the fins have any spots or marks.
Blue marlin have two dorsal fins. The first one starts high and curves to a pointed anterior lobe, with 40 to 45 rays. The second dorsal fin is located just behind the second anal fin and has 6 or 7 rays. The pectoral fins are long, narrow and pointed and can be folded flat against the body. These pectoral fins have 20 to 23 rays and are never stiff, even after death. Pelvic fins are shorter than the pectorals but can be folded in along the side of the body. The two anal fins are comparatively large and pointed. The first anal fin has 12 to 17 rays. The caudal peduncle is compressed laterally and has double keels on each side. The principal way to distinguish blue marlin from their relatives is to examine the shape of the dorsal fin tip, which is more pointed on blue marlin. In addition, the spots found on the fins of most marlin are absent on the blue marlin.
The lateral line of Pacific blue marlin is a succession of chain-like loops that run the length of the flank. The lateral line of the Atlantic blue marlin is more complex and is best described as an interconnected net of loops. In either subspecies, the lateral line is most visible in juveniles and is generally hidden in adults. Like other billfish, they have the characteristic long, spear-like snout, but the snout is shorter and thicker than other marlin. In addition, while most billfish begin growing the bill soon after birth, blue marlin have little identifiable bill growth until they reach about two feet in length. The lower jaw is curved down but has no hook. The roof of the mouth features small teeth.
Blue marlin feed primarily near the surface, though they occasionally dive to deeper water to feed, depending on where their prey is found. Their diet consists mostly of fish and other sea life found near the surface and is highly dependent upon location. This diet can include tuna, mackerel, squid, octopus and any number of fish species indigenous to the environment.
Commercial fishermen report that blue marlin feed in mid to late morning and again in early to mid afternoon. These reports also indicate that they do not feed at night. Observations have been made of blue marlin striking prey with the bill and then eating the victim head first. However, scientists are in disagreement about whether the bill plays a large role in feeding.
Blue marlin can be found in tropical and warm temperate waters throughout the world, mostly in the Atlantic, Pacific and Indian Oceans. It is the most tropical of the billfish and is often found in waters near the equator.
In eastern Pacific waters, they can be found in an area generally running from southern California along the coast of Mexico to Peru in South America. In the western Pacific, they range from Japan to northern Australia. In the Indian Ocean, blues are found in greatest numbers around Sri Lanka and Mauritius.
The east edge of the blue marlin range in the eastern Atlantic runs along the coast of Africa, principally between Gabon and Mauritania. In the western Atlantic, they are sometimes seen as far north as Maine, but mostly south from Florida to the Gulf of Mexico, the Caribbean Sea and south to Brazil and Uruguay. Blue marlin are known to make trans-Atlantic migrations.
Depending on season, large numbers of blue marlin can be anticipated along the warm ocean currents found around the Florida Keys, Cuba, Gulf of Mexico, equatorial regions of the Pacific Ocean and around Hawaii.
Very little is known about the biology of the blue marlin including their migrations and spawning habits. They are known to be a highly mobile species that travels the warm ocean currents with the seasons in search of comfortable water temperatures. This species inhabits depths up to about 600 feet and water temperatures between 70 and 86 F. They are primarily an offshore species found along the edges of continental shelves, near oceanic mountains, underwater canyons, especially near a warm ocean current. Within these environments, they are most likely to be found near large sources of tuna, mackerel and squid. Although they may occasionally form schools of up to 10 members, as they age they become more solitary in their habits.
- There is an ongoing debate as to whether the Pacific blue marlin and the Atlantic blue marlin are one species, individual subspecies or two separate subspecies.
- In addition to being a highly sought-after sport fish, blue marlin are also aggressively pursued by commercial fishermen. The pale, firm meat is considered to be high quality meat, especially when smoked. It is particularly popular in Japan where it is used in fish sausages, sushi and sashimi. Blue marlin is rarely consumed in North America and most of the recreational catch is released.