Sailfish Secrets Revealed in New Study

Unprecedented satellite-tagging research shows surprising migratory patterns and deep dives

Sailfish study reveals secrets - closeup of satellite tag
Pop-up satellite tags are worth $4,000 to bean counters and their weight in gold to scientists, since these can show exactly where a sailfish has gone over the course of a year. (The Guy Harvey Ocean Foundation and Virgin United provided most of the PAT tags for this study.)Courtesy The Guy Harvey Ocean Foundation / Large Pelagics Research Center

Tracking Migrations

A new study of the movements and behavior of Atlantic sailfish by the UMass Boston's Large Pelagics Research Center, based on a year’s worth of satellite-tag data has turned conventional thinking (based on conventional-tag data) on its head.

The old wisdom: Sailfish are home bodies, tending toward residency within particular, well-known areas such as South Florida or Isla Mujeres, Mexico.

Sailfish study reveals secrets - migratory-route map
At least one sailfish tagged off the Yucatan traveled all the way to the coast of Brazil, another to the Carolinas, and many ventured throughout the Gulf of Mexico.Large Pelagics Research Center

The new, more accurate wisdom: Sails migrate, often between those identified hot spots. Over the course of the year, sails tagged off Isla Mujeres in the winter and spring went sort of all over, variously dispersing north to productive grounds in the Gulf of Mexico, east to the Caribbean Sea, and south to the South American coast.

The report, Sailfish migrations connect productive coastal areas in the West Atlantic Ocean, appears on nature.com in Scientific Reports, December 2016 (Chi Hin Lam et. al.).

Sailfish study reveals secrets - one fish's route
The ability to track sailfish for a full year showed scientists that the fish can and often do roam over long distances in the western Atlantic.Courtesy Large Pelagics Research Center

“We tagged this first sailfish off the Yucatan, where it hung out for a short while,” says Tim Lam, PhD, of the Large Pelagics Research Center, of the map above. “It then traveled to the center of the Gulf of Mexico before heading west past Cuba and eventually ended up off the Florida and Georgia coasts.”

The sailfish decided after that to make the trek back to the Yucatan exactly one year later. “Our PSAT tag popped off 18 miles (29 kilometers) from where this sailfish was originally tagged!

“This sailfish definitely knew where it was going,” Lam says, “as if it has its own GPS and Google Maps. Yes! Without a smartphone.”

Although the unprecedented study has shown sailfish to make seasonal migrations connecting multiple coastal areas in the western Atlantic, no trans-Atlantic movement was documented. So far, such trans-oceanic crossings by sails are unknown.

Tracking Behavior

This ambitious study, tagging sails with pop-up archival and satellite tags, also tracked the behavior of sailfish to uncover little-known secrets.

Sailfish study reveals secrets - implanting a satellite tag
Quickly, researchers must implant a satellite tag and measure a sailifish, plus cut a tiny piece of its dorsal fin for genetic analysis.Courtesy Capt. Anthony Mendillo / Large Pelagics Research Center

Among the notable discoveries, most of the tagged sailfish spent most of their time from the surface to about 150 feet down. But at least one fish dived to well over 1,500 feet, where water temperatures were barely over 50 degrees F. And all fish showed activity during darkness (and during all moon phases).

Sailfish study reveals secrets - releasing a tagged sailfish
Ruben Peña carefully puts a tagged sail over the transom for a gentle release.Courtesy Capt. Anthony Mendillo / Large Pelagics Research Center
Sailfish study reveals secrets - Large Pelagics Research Center
For a more personal perspective on this remarkable study, see the blog "Riding with Sailfish to Northwest Atlantic Ocean Hotspots" by Tim Lam, associate research professor with the University of Massachusetts' Large Pelatics Research Center in Gloucester, Massachusetts.Large Pelagics Research Center