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Blue Marlins: A Brief Analysis

Larry Slawson received his master's degree from UNC Charlotte. He has a keen interest in biology and microbiology.

Photo of a blue marlin

Photo of a blue marlin

Blue Marlin: Quick Facts

  • Common Name: Blue Marlin
  • Binomial Name: Makaira nigricans
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Istiophoriformes
  • Family: Istiophoridae
  • Genus: Makaira
  • Species: M. nigricans
  • Conservation Status (IUCN): “Vulnerable”
  • Other Names: Atlantic Blue Marlin; Pacific Blue Marlin; Cuban Black Marlin; Marlin Azul; Castero; Aguja Azul; Abanco; Espadon; Makaire Bleu

The blue marlin is a member of the istiophoridae family of billfish and is recognized as one of the foremost big game species in the world due to its incredible size, strength, power, and aggressive behavior. As a result of its pale yet firm flesh, the large fish is often used to make various sausages as well as sashimi dishes in the Far East. This is in stark contrast to blue marlin that are caught in North America, where the fish is seldom eaten and is often released by anglers soon after being caught.

The blue marlin is easily identifiable due to its rubbery pectoral fins and a high dorsal fin that is high and pointed. The typical coloration of the blue marlin is cobalt blue along with its backside and flank areas, with the underside being a mixture of silver and white. Occasionally, blue marlin also possess light blue, vertical stripes along their sides. However, these stripes are not easily recognizable and often disappear soon after death.

Currently, the blue marlin is the largest species of marlin known to exist in the Atlantic Ocean and occasionally grows to lengths that exceed that of the black marlin. It is also believed that blue marlins grow much larger in the Pacific Ocean, reaching weights close to 2,200 pounds. Females are also much larger than the males, with males rarely exceeding weights of 300 pounds. Finally, and most critically, the average life span of blue marlins is around ten years, with some fish living as long as fifteen years (rarely).

Despite being a popular game fish, relatively little information is known about its behavior and migratory behavior.

Blue marlin (underwater)

Blue marlin (underwater)

Natural Prey and Predators of the Blue Marlin

Blue marlin typically feed on a variety of squid and pelagic fish. They are also known to feed on mackerel, tuna, and occasionally smaller dolphins when food supplies are low. In reality, though, the blue marlin is not known to be selective in its prey and often feeds on whatever it can readily consume. This is due, in part, to their relatively large size which requires a substantial amount of food on a daily basis. Using its long bill to either injure or temporarily stun its prey, the blue marlin is a formidable opponent to nearly any fish species.

Upon reaching full maturity, the blue marlin has very few natural predators due to its enormous size. However, large sharks and killer whales have been known to feed on the marlin periodically. Marlins are actually more likely to be killed by fishermen and an array of diseases/parasites that include digenea, didymozoidea, gillworms, tapeworms, roundworms, spiny-headed worms, copepods, and barnacles.

Habitat and Geographical Distribution

The blue marlin is considered a pelagic and migratory species and is typically found in warm, tropical waters around the world. In the Atlantic Ocean, the marlin is predominantly located around areas corresponding to 45 Degrees North to 35 Degrees South Latitude, whereas marlins in the Pacific favor the latitudes of 48 Degrees North to 48 Degrees South. In these offshore areas, the blue marlin generally prefers deeper depths, as well as various underwater environments that include drop-offs, canyons, seamounts, and ridges.

Marlins also appear to be attracted to areas associated with the Loop Current in the Gulf of Mexico, as well as a variety of other currents worldwide. Researchers believe that this is due, in part, because of the abundance of baitfish that thrive in these areas (a particular favorite of the blue marlin).

Blue Marlin Quote

"I love to fish. You can go hours without anything happening, and all of a sudden a big blue marlin comes into the spread and it's cockpit chaos. My dream is to catch a grander, a 1,000 pounder."

— George Strait


The blue marlin reaches sexual maturity around the age of two to four years of age. They are known to breed in the summer and fall months; however, females have been recorded spawning upwards of four times in a single season. Upon giving birth, the female releases nearly seven million eggs that are each a millimeter in diameter. Very few of these eggs ever develop, though, with most dying prematurely. Upon hatching, the young larvae grow extremely rapidly (as much as 0.63 inches in a single day). Similar in appearance to the adults, the larvae continue to develop quickly over the next few days and months, feeding upon various zooplankton and other fish eggs for nourishment.

Conservation Efforts

In more recent years, the blue marlin has been the subject of intense conservation efforts due to overfishing worldwide. With a large increase of both Japanese and Cuban fishermen in the Caribbean, it is estimated that nearly a thousand tons of blue marlin are caught annually. Recent efforts by the United States to save the dwindling populations have been moderately successful, as all vessels within 200 miles of the United States coast are now required to release all forms of billfish (which include marlins) that are caught. In 2010, Greenpeace has also added the blue marlin to its red list in an attempt to bring greater attention to the animal’s rapidly declining numbers.

Discovering the Unknown

In closing, the blue marlin is one of the most fascinating sea creatures of the world due to its beautiful appearance, natural characteristics, and aggressive behavior. As a prized game fish, populations of the blue marlin have reduced dramatically in more recent years, particularly in the Far East, as the marlin remains a key component to a variety of seafood dishes in the region. With numerous conservation efforts aimed at restoring the blue marlin’s population figures, only time will tell whether these measures are enough to save the marlin from extinction in the years ahead. While much is known about the blue marlin, there is still more to be learned about this extraordinary creature. With research on the marlin increasing in recent years, it will be interesting to see what new forms of information can be learned about this incredible sea creature in the years and decades that lie ahead.

Works Cited


"Blue Marlin." National Geographic. September 21, 2018. Accessed August 07, 2019.


Wikipedia contributors, "Indo-Pacific blue marlin," Wikipedia, The Free Encyclopedia, (accessed August 5, 2019).

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2019 Larry Slawson


Larry Slawson (author) from North Carolina on August 06, 2019:

Thanks Eric! I always thought that as well haha!

Eric Dierker from Spring Valley, CA. U.S.A. on August 06, 2019:

Cool. Wow what an exciting fish. Thanks for this. I had thought a Marlin was just a gigantic tuna. I also thought that the cause of near endangerment was tuna net fishing.

For some reason Hemmingway comes to mind here.

Larry Slawson (author) from North Carolina on August 05, 2019:

Thank you Pamela. I was wondering the same thing. You might be right. That would definitely have an effect on them, I would think.

Pamela Oglesby from Sunny Florida on August 05, 2019:

The blue marlins are attractive with their blue color. I knew of them but really no details. I wonder why they are larger in the Pacific? Maybe over many years, they have had a better source of food. I found this article to be well-written and very interesting Larry.

Larry Slawson (author) from North Carolina on August 05, 2019:

Thank you Liz! I think you might be right. I seem to remember something about that as well haha.

Liz Westwood from UK on August 04, 2019:

This is a great fact file. I have it in mind that many years ago when cinemas showed a short before the main movie, I saw a conedy where a man fishing on a boat caught a marlin, which speared him. It's a vague recollection and it might have been a different breed.