Blue marlin (Makaira nigricans) are some of the biggest, fastest — and most beautiful fish in the world. The challenge they present once hooked was chronicled perhaps most famously in Hemingway’s The Old Man and the Sea. Their power, beauty, and scrap keeps reelers going after them again and again, sparing little in the way of time or money to hunt these incredible creatures.
Blue marlin, like all other marlin, are billfish, with a characteristic, spear-like protrusion from their upper lip. Also, like other billfish, they have a tall, blade like dorsal fin. But on blues, it extends down the spine toward the tail. Blues can be distingusihed by their deep blue coloring on top and a white, almost silver underbelly. Lighter blue stripes appear perpendicular to the spine, and a yellowish strip may be present along the sides. When agitated, blue marlin “flash” — and their colors become even brighter.
Where are they?
The short answer is, pretty much everywhere — well, anywhere they want to be that is. Blue marlin can be found in tropical and temperate waters of the Atlantic, Pacific, and Indian Oceans. But they’re pelagic, which means they’re blue water fish, and extremely migratory. They cruise warm ocean currents — ranging hundreds or even thousands of mile — looking for their next meal and, when it’s time to mate, other blue marlin.
Blue marlin are generally broken down into two varieties or geographic subspecies: Atlantic and Indo-Pacific, named after the bodies of water where they can be found. Regardless of the ocean in which you go looking for them, rest assured that the blues will be the biggest, baddest marlin around.
What do they eat?
The metabolisms of blue marlin keep them close to the surface, where they prefer warmer water. There, they’ll chase tuna and mackerel, using their bills to slash at schooling fish and then eating any fish they stunned or wounded in the process.
They will also dive into the depths to hunt squid. This, of course, explains why squid-shaped baits, like Kona rigs can be effective when trolling for blue marlin.
How big do they get?
They get really big. Female blue marlin, which can be three or four times larger than males, can grow to as long as 14 feet and weigh close to 2,000 pounds. Males, on the other hand, rarely get larger than 8 feet and 350 pounds.
One thing that partially explains the size difference is that females (27 years, on average) live significantly longer than males (18 years). Average blue marlins (both genders) run in the 200 to 400-pound range and are typically 7 feet, or so.
The IGFA all-tackle world record for a Pacific blue is 1,367 lbs (624.14 kg) and was caught off Kona, Hawaii. The record Atlantic blue was 1,402 Lbs, 2 oz (636 kg) was caught off Vitoria, Brazil. But IGFA records adhere to a lot of rules regarding assistance from other reelers and how their caught.
In 1970, an 1,805 lb blue (“Choy’s Monster”) was hauled in by rod and reel off Honolulu. Due to some technicalities, however, IGFA could not certify the record, in spite of the giant fish and its scale-crushing weight. By all accounts, it stands as the biggest marlin boated by rod and reel.
Longline fishermen have reported blues in excess of 2,000 lbs.
One legend that’s been immortalized by a statue in Cabo San Lucas has a commercial fisherman hauling in a 4,500-pounder. They say the monster (“El Marlin”) had to be chopped into three pieces just to be weighed.
Although they’re not yet listed as threatened or endangered, conservationists and reelers alike believe blue marlins — and all billfish, really — are being unsustainably fished, especially in the Atlantic.
Evidence of this is declining catches of truly big fish. For this reason, groups like IGFA and the Billfish Foundation encourage catch-and-release angling. Many tournaments now have a catch (or tag) and release option, and several are tag-and-release only.