With a dorsal fin or “sail” three times the depth of its body, the sailfish is not tough to identify. It’s one of the most beautiful of all fish, capable of “lighting up” when excited to display shimmering purple neon phosphorescence along the shoulders. Its great speed, approaching 60 mph according to some estimates, and its leaping ability also mark this most graceful of the billfishes, making it a favorite target of Florida anglers.
Sails spawn from March through October, with the peak May through August, sometimes in water as shallow as 30 to 40 feet along the Atlantic coast, but nearer the edge of the continental shelf at 200 feet or more in the Gulf. A large female may produce over 4 million eggs, though each of them is only .85 millimeters in diameter—a little larger than the period at the end of this sentence. The egg-mass in spawning fish may make up 10 percent of the body weight. One or two males typically join each female at the spawn, with the eggs usually released over inshore reefs at the surface.
Sailfish, like tarpon, don’t look much like adults at the larval stage. They’re stubby, big-headed and boast a toothy, alligator-like mouth half as long as their body. Fortunately, they’re only 1⁄8 inch long—a big fish this bad would make the seas unsafe for navigation. They don’t look like “real” sailfish until they’re over six inches long. Most don’t survive a full day, but those that do grow fast; they can reach six pounds and a length over four feet in six months. This growth slows down considerably. If it continued, three-year-olds would be 24 feet long. Try that on your 12-weight!
The fish begin to spawn at age three, when the females weigh 30 to 40 pounds, the males 25 to 30 pounds.Researchers studying annuli or growth rings on the spines of an eight-footer weighing about 80 pounds aged the fish at 7. The species lives to about age 15, but 5 is a more typical maximum. The females reach larger size than the males; for fish over 50 pounds, seven females are landed for every male, while the numbers are fairly equal at lower weights. Atlantic sails reach lengths to 10 feet counting the bill, and weights of at least 140 pounds, though a 100-pounder is a rare trophy in Florida waters these days. Average fish weigh 30
to 45 pounds and are four to seven feet long. They give the impression of being much heavier because of the bill and the broad sail. They’re thought to be the same species as Pacific sailfish, though fish in the Pacific are typically larger.
Though sails are often found around flyingfish and near migrating schools of mullet, biologists who study stomach contents say that neither species is a favorite food year-round. They eat a lot of baby mackerel and little tunny, ballyhoo and needlefish, and also chow down on squid. Gulf sails apparently eat a lot of shrimp, as well. They’re primarily daytime feeders; few have been caught after dark, and fish caught early in the morning usually have empty stomachs, while those caught near dusk are often full.
Divers have observed sailfish using their erect sails to fence in schools of baitfish trapped near the surface. The fish circle the baits, occasionally slashing at them with their bills to stun them so that the wounded flutter down to become an easy meal.
Sails prefer water temperature from 72 to 82 degrees when they can find it. This stacks them up in the Gulf Loop, the Florida Current and the Gulf Stream off Florida in winter, but allows them to range northward to the Carolinas and Virginia in summer. They generally migrate north with the baitfish movements in April and return with the southward movements in October and November.
Sailfish numbers in Florida waters appear to be at a modern high thanks to a prohibition on sale and to a total-release ethic among nearly all anglers these days. The only threat to them is longline fishing, which kills many as bycatch.
(Researchers at the Rosenstiel School of Marine and Atmospheric Science at the University of Miami and scientists at the National Marine Fisheries Service assisted in providing biological information for this report.)