blue marlin
Blue Marlin explosion

Leaping blue marlin

Blue Marlin (Makaira nigricans) are considered one of the top apex predators in the ocean. They are renowned for their strength, speed, aggressiveness, and the lethal bill they use to hunt with.  It’s these same characteristics that make them sought after by recreational and tournament anglers. Two subspecies of blue marlin exist – the Pacific and Atlantic blue marlin.

Anatomy and Physiology of Blue Marlin

Blue marlin belongs to the billfish family, which also includes sailfish, swordfish, and spearfish. As its name suggests, blue marlin have a deep blue color on its back and upper sides.  This color fades to silver-white on its lower sides and belly. Marlin have an elongated body that is streamlined and muscular. They have a long bill or spear that it uses to stun or impale their prey, such as tuna or mackerel. Blue marlin can grow up to 14 feet long and weigh well over 1,000 pounds. Most adult males are smaller, 100 to 300 pounds. The females can grow four times as large.  They are an interesting species because they experience an astonishing metamorphosis in size throughout their life. They start out as small larvae and mature into one of the largest predators in the ocean.

Eating Habits

Their eating habits are diverse and alter as they grow.  Feeding starts with the consumption of tiny zooplankton during their juvenile stage and transitions towards larger bony fish and squid during adulthood. In their early life phases, they are the targets of plankton-consuming fish. Larger fish will prey on them as they continue to grow. Once they are an adult, blue marlin are formidable and are only preyed upon by large ocean shark species

Temperature and Environmental Adaptations

Marlin is an ectothermic or cold-blooded animal. Their body temperature matches that of their environment. It can tolerate a wide range of water temperatures, from 70 to 90 degrees Fahrenheit, but prefers warmer waters around 80 degrees. Marlin and other billfish do possess a specialized blood vessel arrangement known as a countercurrent exchanger.  This allows marlin to raise the temperature of their brains and eyes. This adaptation is helpful while hunting, it enables marlin to think and see quickly, providing an advantage over their prey.  Marlin is also a highly migratory species.  They can travel long distances in search of food, spawning grounds, and suitable habitats. Populations of blue marlin are found in the tropical and subtropical waters of the Indian, Pacific, and Atlantic Oceans.

Blue Marlin Reproduction

Marlin follow a unique external fertilization process, Females release eggs into the water, and males release sperm to fertilize them. During spawning, a female blue marlin can discharge millions of eggs, ensuring the highest probability of fertilization and hatching, resulting in the progression of at least one larva into adulthood. Males court female blue marlins by swimming in circles, flashing their colors, and using their bills to tap or push the females.

Adult Life

Adult blue marlin feed on a variety of prey, mostly tuna, but also squid, mahi-mahi, and smaller bait fish.  Due to widely accepted catch-and-release practice, the Pacific and Atlantic blue marlin stocks remain relatively healthy around the world.

Blue marlin have distinct traits and attributes, making them one of the world’s top game fish. Unlike white marlin, blue marlin have a tall, anteriorly pointed dorsal fin and similarly pointed anal fin. The marlin’s coloration is marked by dark blue above the lateral line and silver/white below. Blue marlin weighing over 1,000 pounds are known as “granders”. The largest Atlantic blue marlin IGFA record is 1,402 pounds, caught in Vitoria, Brazil, in 1992 by Paolo Amorim, while the largest Pacific blue marlin IGFA record is 1,376 pounds, caught in Kona, Hawaii, in 1982 by Jay de Beaubien.

Sportfishing – The Thrill of the Hunt

The blue marlin is one of the most popular big game fish, attracting recreational anglers and tournament participants every year.

Live Bait Fishing

Marlin can be caught using a wide variety of fishing techniques, with trolling being one of the most productive. Another technique is using natural live bait, such as tuna. Circle hooks have become a mainstay in this type of fishing. Live baiting is popular, but it is more limited to specific areas that are known to hold marlin, including “The Grounds” off the Kona Coast, offshore seamounts, and deepwater oil and natural gas rigs in the Gulf of Mexico.

Lure Fishing

One of the more efficient ways to catch a blue marlin is by trolling four or five lures with heavy or lighter tackle. Captains and crew select different colors and styles of lures depending on the position in the lure spread, weather/water conditions, and the type of baitfish in the area. The most popular fishing spreads consist of larger, more active lures fished closer to the boat and smaller, straight-running lures farther back from the outriggers. Popular lure brands are Tantrum, Black Bart, Aloha, Koya, Marlin Magic, Bonze, and others. Fishing with artificial lures allows the angler to troll at a higher speed to cover more ground to encounter hungry marlin.

Most fisheries honor catch and release practices for blue marlin.  The exception would be tournaments if it is a “qualifier” or food consumption.

If you are interested in fishing for blue marlin in Kailua-Kona, HI, contact us to find out more details.


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