These unique, solitary roamers are found in warm and temperate waters around the world. A swordfish’s bill is different from those of other billfish like marlin. Instead of being rounded, a swordfish’s bill is edged – like a sword. Hence the fish's scientific classification: xiphias gladius, or 'sword sword' in Greek and Latin, respectively.
Swordfish are known for their ferocity. In the 1800s, they attacked whaling ships with some frequency. In one recorded case, a swordfish drove its bill through a layer of copper sheathing, an inch of wooden undersheathing, a three inch hardwood plank, a 12 inch timber of white oak, finally imbedding it in the head of an oil cask!
Swordfish are pursued worldwide by the fleets of more than 20 nations. In the U.S., swordfish are landed from Maine to Louisiana, as they migrate up and down the East Coast. U.S. swordfish catches peaked in 1993 at just over 10,000 metric tons. In recent years, following the introduction of a variety of conservation measures, U.S. catches have fluctuated between 3,500 and 4,000 metric tons. In 2011, Hawaii was the leading swordfish producing state followed by Florida, California, North Carolina, South Carolina and Massachusetts. Virtually all the U.S. catch is sold fresh.
In the Atlantic, almost all swordfish are caught with longlines, although very small volumes are landed by harpoon and hook-and-line. In the Pacific, the Hawaiian sword fleet uses longlines, while California fishermen use gillnets.
The U.S. imports about 10,000 metric tons of fresh and frozen swordfish a year. Singapore and Chile are the primary sources of frozen swordfish, while Canada and Ecuador are the primary suppliers of fresh.
Fresh swordfish are available year round, but peak catches are in the fall when landings are still good on the East Coast and the California fishery, which runs from August to January, is in full swing. Prices are generally at their low point of the year in the fall, which makes it a good time to promote swordfish.
Fresh swordfish are sold in trunks (headed and gutted, tail off), chunks or wheels (a cross section of a trunk) and loins, usually skin-on. Swordfish under 50 pounds are called “pups,” 50 to 99 pounds are “mediums,” while 100 pounds and up are called “markers.” The flesh of swordfish caught off California tends to be whiter, while swordfish off the East Coast is a pinker shade.
While swordfish are all the same in the water, that changes once they come out, depending on how well they are handled and how long they’ve been out of the water.
Many buyers look at the characteristics of a swordfish’s “bloodline” to determine its quality. This can be misleading. First, it’s not really a bloodline we are talking about. This darker pigmented meat at the center of a swordfish cross section is actually muscle that surrounds two large blood vessels. These vessels are instrumental in helping the swordfish regulate and maintain its body temperature within a desired range.
A tight muscle area is often associated with the highest quality swordfish. Some buyers believe that as a swordfish carcass ages after it is caught the red muscle area dissipates and extends across a larger area. The reality is that this is not always a reliable quality indicator. Swordfish caught in more northern waters experience a wider range of temperatures as they move up and down the water column in search of food. This results in more adjustments in the fish’s circulatory system and a larger red muscle area. Conversely, swordfish from more tropical waters have less need to regulate their temperatures and hence have a smaller red muscle area.
The color of the “bloodline” is also widely considered to be a quality indicator, with the belief that a brown line indicates the fish has more age on it then a red bloodline. That is not necessarily the case. Improper use of salt water ice on a fishing boat, for example, can lead to a fish’s muscle area turning brown. Since it is colder then freshwater ice, saltwater ice must be allowed to cure, or warm, for a few days to avoid inadvertent freezing of the fish. The color of the bloodline can also be a factor of the time of death, fat content, and level of metabolic by-products of a struggling fish. So simply relying on the size and color of “bloodline” is not always an accurate quality indicator.