Swordfish has a slightly sweet, mild flavor. The texture is firm and meaty, so it is a good fish for grilling. It is a lean cut, though it stays moist through the cooking process as long as it is not overcooked. Swordfish is a nutritious cut of meat. Just 100 grams of swordfish has nearly 20 grams of protein and only 121 calories. It is high in selenium, niacin and vitamin B12.
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 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.