Scientists, with help from recreational anglers, commonly use tags to study highly migratory species. When a fish of interest is caught, such as the iconic sailfish, we measure it and record its location before releasing the fish with a tag in place. If and when the fish is recaptured (and, just as importantly, when the recaptured tag is reported to us), we can collect additional data. This helps us estimate their age and lifespan, migration patterns, and habitat ranges. Sometimes, the information we collect from these opportunities is surprising—as with the sailfish recaptured this season.

On December 30, 2023, two tagged sailfish were recaptured within hours of each other in South Florida—but the fortuity doesn’t stop there.

The First Sailfish

The first sailfish was at large for exactly 1 year to the day. It was recaptured on December 30, 2023, by the same captain, Paul Ross. He was fishing on the same vessel, Relentless, and at the same site—Eagle Wreck—where it was first tagged in Islamorada, Florida, on December 30, 2022.

So, what does this tell us about this fish? We know that the fish came back to the same bottom feature (a sunken ship in this instance) within the same time period. We know it was feeding on the same type of bait both times. Animals don’t follow a calendar like humans do. In this case, it’s more likely seasonally driven environmental conditions and prey availability that attracted the fish to the same area on the same day.

Derke Snodgrass, a fishery biologist with NOAA Fisheries’ Cooperative Tagging Program added, “Considering that this shipwreck is fished year-round by many boats, and this fish was not reported to have been caught at any other time, tells us that the fish likely didn’t stick around this wreck throughout the year. It likely traveled great distances but decided to come back to this same region—even though it experienced a traumatic event like being captured!” Without this tag and the recapture report, we would never know that these fish exhibit a pattern of returning to the exact same location—exactly 1 year later.

Sailfish Two

Even more astonishing is that also on December 30, 2023, a second sailfish recapture of the day occurred 30 miles away. The second sailfish was at large for exactly 2 years to the day. This fish was originally tagged at Alligator Reef, off of Islamorada, Florida, by Captain Alex Adler on the fishing vessel Kalex on December 30, 2021. It was recaptured less than 40 miles away from its original location at Carysfort Reef off of Key Largo, Florida, by Captain Nick Favata and anglers John Weiland and Colleen McKeon on the vessel Big Game. The kicker: The boats Relentless and Kalex are sister ships made by the same manufacturer and are docked at the same marina.

A Flurry of Sailfish Recaptures

A few days later, on January 3, 2024, another recapture report came from the fishing vessel Relentless from Eagle Wreck again! This was followed by yet another recapture report from the fishing vessel Vice Versa team on January 4, 2024. This one was caught by Captain Sam Milazzo and angler Nick Jones at Conch Reef—about 10 miles north of the previous recapture.

The catch to this set of recaptures is that they were both originally tagged and released by Captain Nelson De La Torre from the same boat in Miami, The Billin’ Office.

What Does This Mean?

Recapture seasons always appear to be fairly busy. However, it isn’t often that incidents like these occur.

“That was quite a set of recapture for less than a week of time.” says Snodgrass. “Having two fish recaptured on the same day is rare. Having them within exactly one year and two calendar years at large has never occurred before, to our knowledge. What this tells us is that sailfish follow some sort of patterned behavior that we haven’t been able to crack yet.” These data will be instrumental in deciphering the code of sailfish migratory behavior.

Having two fish recaptured within a day from the same tagger only 10 miles away from each other is also quite rare. Sailfish are generally considered solitary fish, but these tagging data may provide evidence that sailfish do travel together along the same pathways. Perhaps they don’t behave as a traditional school of fish, but may swim along some sort of a preferred route as a spread-out group.

Although it may seem like a remarkable coincidence, these findings may actually reveal systematic migration patterns sailfish follow throughout the year. More sophisticated tags, such as electronic archival tags, may be able to help us truly determine why such occurrences happen.

A map of the 2023-2024 sailfish recaptures. Credit: NOAA Fisheries.

Why Tag Billfish?

NOAA collaborates with The Billfish Foundation and Gray FishTag Research to collect data on targeted fish populations. Billfish (blue marlin, white marlin, roundscale spearfish, and sailfish) are Atlantic Highly Migratory Species. Tagging allows scientists to learn more about when and where fish migrate and their range of habitat. This method also helps us track seasonal patterns, shifts in behavioral changes, and how well fish recover after being released. More broadly, these data help us better understand highly migratory species, identify essential fish habitats in U.S. waters, and sustainably manage the fishery.

Cooperative Tagging Program

In addition to the research and management benefits, the Cooperative Tagging Program invites people to be involved in citizen science, learn more about these fish, and be better connected to their target species. The Cooperative Tagging Center is one of the longest running tagging programs in the world. It has been working with recreational anglers and commercial fishermen since 1954. The program distributes fish tags to individuals who regularly catch and release various highly migratory species. Captains and anglers are rewarded for reporting recaptures. Additionally, all recaptures go into an annual lottery drawing done by the International Commission for the Conservation of Atlantic Tunas for a $500 reward.

To request a free tagging kit, or to report a recapture, contact the Cooperative Tagging Center at (800) 437-3936 or at tagging@noaa.gov.

More Information:

Cooperative Tagging Program

Citizen Science Helps with Rare Sailfish Recaptures

Saving Fish for Tomorrow: Tagging Provides a New Lens on Charter Fishing

Filling the Gap: Tagging Highly Migratory Species in Curaçao

Oceanic and Coastal Pelagics Branch

Southeast Fisheries Science Center