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What is a Marlin?

Jessica F. Black
Jessica F. Black

A marlin is a beloved sporting fish and is often classified into two categories: Pacific and Atlantic marlin. Both oceans have specific breeds of marlins — striped, black and Pacific blue marlins inhabit the Pacific Ocean, and Atlantic blue and white marlins occupy the Atlantic Ocean. There are extreme physical differences between the five marlin subgroups, including weight, length and markings, but biologically, they are similar. They are equipped with long, sleek bodies and a spiked bill, which encloses small, sharp teeth. For many anglers, the marlin is the primary choice of game fish, because of its intimidating size, defensive nature, speed and beauty, making it a valuable trophy fish.

The basic structure of the marlin is heavily boned with a variety of essential fins. Marlins have two dorsal fins sprouting from their backs, two anal fins protruding from underneath their bodies, one pectoral fin on each side of the body near the gill cover, two pelvic fins lower and further back than the pectoral fin and a caudal fin, which is the tail that concludes its graceful body. Their fins and bone structure contribute to their speed, which poses a challenge for their captors and increases the competition in sport fishing.

There is concern that marlins have been overfished by both commercial and sport fishermen.
There is concern that marlins have been overfished by both commercial and sport fishermen.

The striped and white marlin are smaller in size than their counterparts. Their average weight of 70-200 pounds (about 31-91 kg) might be impressive to a cod fisherman but not in comparison to the blue marlin's weight that often exceeds 1,000 pounds (453 kg). A marlin, depending on its breed, can reach nearly 20 feet (6 m) in length. Its weight can be attributed to its diet, which includes a diverse appetite for countless fish. Marlins feed on most fish of a lesser size.

The difference in color between the breeds is distinct, and each marlin has a trademark appearance. The blue marlin has a shimmering electric blue body that emanates a silver reflection, and at a swimming speed of 70 miles (112 km) per hour, it can resemble a bullet under the water. The black marlin has a shiny black upper half and a white underbelly. The striped marlin has a gloriously unique appearance with a dark blue back gradually melting into a lustrous gray underside and metallic blue vertical stripes throughout its entirety. The white marlin has a predominately pearly white body, but there is a small portion of his upper back that is fluorescent blue with shiny, powder blue vertical stripes.

Female marlins are acutely larger than the males and are often the ones who weigh more than 1,000 pounds (453 kg). Their mating season usually begins in mid-summer and lasts through most of the fall. Although a large portion of their spawn do not make it to adulthood — a significantly small number out of millions — their ability to breed two to three times a season assists their number in existence.

Marlins are purchased for human consumption, and recipes range from grilled marlin to teriyaki marlin. An increased effort has been made to remove marlin from the market because they have been captured more quickly than they are able to reproduce. Their inability to be farm-raised, unlike many other store-bought fish, has created a fear that overfishing will lead to their extinction.

Frequently Asked Questions

What exactly is a marlin?

A marlin is a large, oceanic fish known for its elongated body, spear-like snout, and impressive dorsal fin. Marlins are part of the billfish family, which also includes sailfish and swordfish. They are apex predators, feeding on a diet of smaller fish and squid. Marlins are highly prized by sport fishermen due to their size and strength.

How many species of marlin are there?

There are four main species of marlin: the blue marlin, black marlin, striped marlin, and white marlin. Each species has distinct physical characteristics and habitats. For instance, the blue marlin is the largest, with females capable of reaching weights of over 1,000 pounds, according to the International Game Fish Association.

Where can marlins be found?

Marlins are pelagic fish, meaning they live in the open ocean, typically in tropical and subtropical waters. Blue marlins are found in the Atlantic, Pacific, and Indian Oceans, while black marlins are primarily located in the tropical Indo-Pacific waters. Striped and white marlins also have specific ranges within the Atlantic and Pacific Oceans.

What is the average lifespan of a marlin?

The lifespan of a marlin can vary depending on the species. Generally, marlins can live for about 18 to 27 years. The blue marlin, for example, has a longer lifespan, with some individuals living up to 27 years, as reported by marine biologists studying growth rings on the fish's ear bones.

Are marlins endangered?

Some species of marlin are considered to be threatened due to overfishing and bycatch. The International Union for Conservation of Nature (IUCN) has listed the blue marlin as vulnerable, while the white marlin is near threatened. Conservation efforts are in place to manage fishing practices and protect these majestic creatures.

What role do marlins play in the ecosystem?

Marlins play a crucial role as apex predators in maintaining the balance of marine ecosystems. By preying on a wide variety of fish and cephalopods, they help regulate the populations of these species and prevent any single group from dominating the environment. Their presence indicates a healthy, biodiverse oceanic habitat.

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    • There is concern that marlins have been overfished by both commercial and sport fishermen.
      By: B. Wylezich
      There is concern that marlins have been overfished by both commercial and sport fishermen.