Atlantic Blue Marlin

The Atlantic blue marlin (Makaira nigricans) is a species of marlin endemic to the Atlantic Ocean. It is closely related to, and usually considered conspecific with, the Indo-Pacific blue marlin, then simply called blue marlin. Some authorities still consider both species distinct.
The Atlantic blue marlin (hereafter, blue marlin) feeds on a wide variety of organisms near the surface. It uses its bill to stun, injure, or kill while knifing through a school of fish or other prey, then returns to eat the injured or stunned fish. Marlin is a popular game fish. The relatively high fat content of its meat makes it commercially valuable in certain markets. It is the national fish of the Commonwealth of the Bahamas and is featured on its coat of arms.
Blue marlin are distributed throughout the tropical and subtropical waters of the Atlantic Ocean. A bluewater fish that spends the majority of its life in the open sea far from land, the blue marlin preys on a wide variety of marine organisms, mostly near the surface, often using its bill to stun or injure its prey.
Females can grow up to four times the weight of males. The maximum published weight is 818 kg (1,803 lb) and length 5 m (16.4 ft).
Adult blue marlin have few predators apart from killer whales, sharks, and humans. They are sought after as a highly prized game fish by anglers and are taken by commercial fishermen, both as a directed catch and as bycatch in major industrial tuna fisheries. Blue marlin are currently considered a threatened species by the IUCN due to overfishing.
Some other historic English names for the blue marlin are Cuban black marlin, ocean gar, and ocean guard.
== Description ==
The biggest females are more than four times as heavy as the biggest males, which rarely exceed 160 kg (350 lb) in weight. The longest females can reach a length of 5 m (16 ft) with the bill, from eye to tip, constituting about 20% of the total body length.
Body mass in the largest female specimens has been reported from 540 to 820 kg (1,190 to 1,810 lb), depending on the source (few large specimens are scientifically verified). The largest blue marlin caught by IGFA angling rules is from Vitoria, Brazil, which weighed 1,402 lb (636 kg).; fishermen often refer to individual marlins that reach or exceed 1,000 pounds as "granders".
Both sexes have 24 vertebrae, of which 11 are precaudal and 13 are caudal.
The marlin has two dorsal fins and two anal fins. The fins are supported by bony spines known as rays. Its first dorsal fin has 39 to 43 rays from front to back. Its second dorsal fin has six or seven rays. Its first anal fin, which is similar in shape and size to the second dorsal fin, has 13 to 16 rays, and the second anal fin has six or seven rays. The pectoral fins, which have 19 to 22 rays, are long and narrow and can be drawn in to the sides of the body. The pelvic fins are shorter than the pectorals, have a poorly developed membrane, and are depressible into ventral grooves. Its first anal fin, along with its pectoral and caudal fins, can be folded into grooves. This streamlines the fish and thereby reduces drag.
Blue marlin, like other billfish, can rapidly change color, an effect created by pigment-containing iridophores and light-reflecting skin cells.
Most often, however, the body is blue-black on top with a silvery white underside. It has about 15 rows of pale, cobalt-colored stripes, each of which has round dots and/or thin bars, located on both sides of the fish. The first dorsal fin membrane is dark blue or almost black and has no dots or marks. Other fins are normally brownish-black, sometimes with a hint of dark blue. The bases of the first and second anal fins have a hint of silvery white.
The body is covered with thick, bony, elongated scales that have one, two, or three posterior points, with one being the most common form.
The bill is long and stout. Both the jaws and the palatines (the roof of the mouth) are covered with small, file-like teeth. The lateral line system is a group of neuromasts rooted in lateral line canals that can sense weak water motions and large changes in pressure. It has the appearance of a net. It is obvious in immature specimens but unclear in adults, becoming progressively embedded in the skin. The anus is just in front of the origin of the first anal fin.
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