The Atlantic blue marlin is a species of fish belonging to the family Scombridae, commonly known as mackerel sharks. They are found worldwide in tropical waters near coral reefs, usually in groups of about 30 individuals. Their length varies from 2 m to 5 m; females tend to grow larger than males. Marlin reach sexual maturity around 10–12 years old, though some mature much sooner. Females bear live young and produce eggs every month during the spawning season.
Blue Marlin fish are highly migratory, moving long distances between feeding grounds and breeding areas. Most marlin spawn off South Africa and spend most of their lives there. However, due to overfishing, many populations have been depleted. In the 1980s, the International Union for Conservation of Nature declared the Atlantic blue marlin to be critically endangered. As of 2018, it is listed as vulnerable.
Family : Scombridae
Genus : Macruronus
Species : M. australis
Common Names : Blue marlin, Australian marlin, Cape blue marlin, Southern blue marlin, Tasmanian blue marlin, Tasman Sea marlin, West Indian blue marlin, West Pacific blue marlin
Size of Blue Marlin fish
The average size of a female panda is about 10 feet long and weighs around 500 pounds. Males typically measure 12 feet and weigh up to 700 pounds. However, some females grow even bigger than that. In fact, one giant panda named Tian Tian weighed 2,100 pounds when she died in 2017. She was the largest panda ever recorded.
Coloring and Characteristics
The blue marlin is one of the largest species of billfish, reaching lengths of up to 4 meters (13 ft). This fish lives in warm oceanic water, usually over 300 m deep, feeding primarily on squid and smaller fishes. Blue marlins inhabit the tropics and subtropics throughout the world’s oceans. They are found in the western Atlantic Ocean from Bermuda to Brazil, including the Gulf Stream; in the Caribbean Sea; off South Africa, Namibia, Mozambique, Madagascar, India, Sri Lanka, Indonesia, Australia, New Zealand, and Japan; and in the Mediterranean Sea. In the Pacific Ocean, they occur from southern California northward to Hawaii, Samoa, Tonga, Fiji, Vanuatu, New Caledonia, French Polynesia, Easter Island, Chile, Peru, Ecuador, Colombia, Venezuela, Trinidad, Guyana, Suriname, Brazil, Argentina, Uruguay, Paraguay, Bolivia, and Peru.
In the Indian Ocean, blue marlins live along the coastlines of East Africa and south into the Arabian Sea, Persian Gulf, Red Sea, Somali Basin, Bay of Bengal, and Andaman Sea. They migrate seasonally, following the monsoon winds.
They swim slowly, moving at speeds of about 1–2 knots (1.8–3.6 km/h), and feed mostly at night. Their diet consists mainly of small pelagic fishes such as sardines, mackerels, herring, anchovies, tunas, jack crevalle, and sharks. Blue marlins prey on schooling fish, especially tuna, while sometimes taking large sharks. When threatened, they retreat to deeper water where they hide beneath the surface.
A study published in 2010 showed that blue marlins are capable of hunting down schools of bait fish, using their long snouts to probe the depths for prey. However, the researchers noted that blue marlins rarely attack larger fish like swordfish, sailfish, and tuna.
Habitat and Diet
Blue marlin live in tropical oceans around the world, including off South America, Africa, Australia and Asia. Their preferred habitat is warmer water near coral reefs, where they feed on small schooling fishes like mackerel and tuna. In the open ocean, they hunt large pelagic species such as tunas, billfish and sharks.
They spend much of their lives far out to sea, following warm ocean currents for hundreds or even thousands of miles. But they are also highly migratory; some will travel hundreds of miles each season to follow the seasonal changes in food sources.
Commercial and Sport Fishing
Known for putting up a tremendous struggle when hooked, these rare sea monsters are the holy grails for sport fishers. They’re called blue sharks because of their deep blue coloration and, although not currently endangered, conservation groups worry that they are being unhealthily overfished, particularly in the North Atlantic. A single shark can weigh up to 300 pounds and grow to lengths of 20 feet. Blue sharks are found worldwide, though they are most abundant near Australia and South Africa. In fact, there are more blue sharks off Cape Town than anywhere else in the world, according to the World Wildlife Fund.
Blue sharks have been around since prehistoric times. But commercial fishing began in earnest in the early 1900s, when the British Empire needed a source of protein for canned fish. Today, the United Kingdom is one of the largest exporters of blue shark products. Other countries like Spain and Portugal also catch and export the animals.
The meat is considered a delicatessen, particularly in Japan, and is served raw as sushimi. Because blue sharks live in cold water, they must be kept alive while they’re harvested. This usually involves keeping them in tanks of seawater at room temperature. Once caught, the sharks are skinned, gutted, eviscerated, cut into steaks, and frozen.