Whether you refer to them as swordfish, broadbills, or by their scientific name, Xiphias gladius, these majestic creatures are among the most powerful predators in the ocean.
These fish can grow to upwards of 1,400 pounds and 14-feet in length, making them one of the largest predatory fish in the sea.
These unique predators are a scientific marvel in how they hunt, feed, and spawn. Today, we’re going to cover everything you need to know about this incredible sportfish, from its characteristics and appearance to its lifespan, reproduction, habitat, eating habits, and much more.
Table of Contents
Characteristics & Appearance
Swordfish are among the largest and most interesting-looking pelagic fish in the world. Let’s take a closer look at the unique characteristics that make this creature so fascinating.
Weight & Length
Mature swordfish are massive creatures. At full maturity, these fish regularly eclipse 1,000 pounds and 12-feet long. The world’s largest recorded Swordfish was over 1,400 pounds and nearly 15-feet long.
Considering how tiny baby swordfish are at birth, the size change while reaching adulthood is remarkable.
Baby swordfish are hardly large enough to be seen by the naked eye and weigh mere fractions of a gram. A swordfish can grow to over one million times its initial size from birth to full maturity.
Physical Characteristics & Color
Swordfish are among the most recognizable and iconic creatures in the ocean, and their unique looks and coloration make them incredibly easy to identify.
Both male and female swordfish have a two-tone body that’s darker at the top before fading to light silver for the lower ⅔rds of the fish.
The dorsal fin and top of the fish have shades of black, dark grey, and brown, while the lower portion of the fish fades to a light silver or white color.
They have a massive dorsal fin followed by a smaller one and two anal fins. Swordfish don’t have any pelvic fins, and their tail is quite large, allowing them to propel through the water at incredible speeds.
Then, there’s the most impressive characteristic, which is the massive sword-like bill of the fish. The “sword” is blunt and rounded, and swordfish use it to stun large prey, so it’s easier for them to eat.
It’s also speculated that swordfish will use their bill as a defensive weapon to protect themselves from sharks and whales.
Lifespan & Reproduction
Swordfish reproduce by spawning near the ocean’s surface. A male and female swordfish will pair off when it’s time to spawn.
The female releases her eggs, prompting the male to release sperm to fertilize the eggs. A female swordfish can release millions of eggs during each spawning session.
Once fertilized, it only takes a few days for the egg to develop a pelagic larvae. Shortly after that, a baby swordfish is born.
The swordfish fry are incredibly tiny, measuring around 1mm long at birth. The baby fish grow rapidly, and once they reach about 5mm in length, they begin to develop their signature bill.
Swordfish reach full maturity by five years and have a lifespan of about 15 years. During their first year of life, baby swordfish are popular prey for sharks, whales, and other large ocean predators.
While it’s somewhat common for mature swordfish to grapple with other ocean predators, they are apex predators with very few natural threats.
Habitat
Swordfish are uniquely adapted to live in various environments, and they can be found in the Atlantic, Pacific, and Indian oceans.
These fish are uniquely adapted to tolerate a broad range of settings, including cold water, warm water, and depths ranging from 3,000 feet to the surface.
While swordfish are coldblooded creatures, they have a unique heat regulation system that warms their brains and eyes, allowing them to hunt in colder waters effectively.
Where Do Swordfish Live?
Thanks to their ability to deliver heat to critical organs, swordfish are able to live in an incredible diversity of environments.
Swordfish prefer to spend their time in waters ranging from 64-72°F, but they can move into much colder waters as needed to hunt. Only a handful of pelagic fish have this ability, including sharks and tuna.
Annually, swordfish migrate thousands of miles each year up and down the western and eastern Atlantic coasts so they can inhabit the most comfortable waters at the time.
Food & Diet
Swordfish are one of the ocean’s apex predators, and they have very few natural predators. These fish prey on a wide variety of fish and cephalopods.
They have been known to feed throughout the entirety of the water column, from the surface to depths as low as 3,000 feet.
What Do Swordfish Eat?
Juvenile swordfish begin their lives feeding on tiny zooplankton and microorganisms. As they reach maturity, they begin to hunt larger prey, including various fish and cephalopods.
Other prey that swordfish eat include squid, octopus, mackerel, and herring. Swordfish feed most voraciously at night, but they’re known to eat at all hours of the day.
These fish mostly eat at or near the surface, but they’re happy to descend to greater depths in search of more food.
During the warmest months of the year, swordfish will regularly hunt at greater depths where the water is cooler.
Swordfish aren’t schooling fish, and they do most of their hunting alone. It’s common to see multiple swordfish together, but they’re usually separated by 20 feet or more as they swim.
While swordfish eat most of their prey whole, when they attack larger prey, they’ll often use their bill as a weapon.
Swordfish don’t stab at their target with their bill; they will thrash it back and forth to stun fish and make them easier to attack.
Threats & Predators
As apex predators, swordfish don’t have nearly as many factors threatening their safety as smaller fish do. Still, swordfish are threatened by various factors, including humans, climate change, and other apex predators.
Human Threats
Humans present the biggest threat to the lifespan of swordfish, mostly in part because they are prized as sportfish.
Swordfish put up an incredible fight, and it’s common for them to leap from the water and tail walk several times as the angler fights the fish to the boat.
Beyond putting up a fierce fight, few fish make a more iconic trophy than the majestic swordfish.
Thousands of anglers target swordfish each year in hopes of landing one of these impressive pelagics.
Climate Change & Global Warming
Since swordfish can tolerate such a broad range of water types and temperatures, they aren’t as susceptible to forces like climate change and global warming as other fish.
Pelagic species such as swordfish aren’t subject to habitat destruction or changes in water chemistry the way that smaller inshore fish are.
Predators
As an apex predator, very few species pose a threat to swordfish. Swordfish are incredibly large and have a powerful defense mechanism in their bill.
Above all, they’re one of the fastest pelagics in the ocean, so they’re able to avoid danger presented by other large pelagics.
Other Threats
Except for anglers, occasional predation, and global warming, the only other threat swordfish experience is parasites.
Remoras, lampreys, cookiecutter sharks, and various worms are common to find on swordfish.
It’s believed that when the fish breach the surface of the water, they’re doing so to dislodge parasites.
Conservation Status
Despite swordfish being one of the most popular sportfish for anglers to target, their population is strong, and according to the IUCN, swordfish have the conservation designation of least concern.
The population is holding firm, and several initiatives are in place to protect swordfish in areas where their population is threatened.
Fun Facts About Swordfish
Still eager to learn more about these impressive pelagics? Here are some fun facts about these incredible fish.
- Swordfish have a unique organ near their eyes that warm their brains and eyes, allowing them to hunt in colder waters
- Except for marlin and sailfish, swordfish are the fastest fish in the ocean
- The largest recorded swordfish was over 1,400 pounds and nearly 15-feet long
- Swordfish will thrash their bill back and forth to stun and incapacitate their prey
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