In December 2022, the Marlin Fly Project completed the first documented satellite-tagging mission for striped marlin caught entirely on fly tackle, deploying 15 satellite tags in just 24 hours off Magdalena Bay, Mexico.
Established through a partnership with Costa Sunglasses, the project brought together The Billfish Foundation, the International Game Fish Association, the University of Southern Mississippi’s Center for Fisheries Research and Development, Los Locos Mag Bay, experienced fly anglers and guides from around the world, and local captains.
Since the inaugural expedition, The Billfish Foundation has continued deploying satellite tags annually through the Marlin Fly Project, building a growing dataset on striped marlin movements, habitat use and survival after release.
TBF will return in December 2026 to deploy further satellite tags as part of its 40th Anniversary and 40 for 40 campaign.
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Each fall, striped marlin gather off southwestern Baja to feed on concentrated schools of baitfish, creating an extraordinary fishery that supports local guides, businesses and visiting anglers. The Marlin Fly Project connects research with this community to better understand and protect the fishery they share.
Local captains and guides contribute the knowledge that makes tagging possible. Through Los Locos Mag Bay, visiting anglers participate in the research, including helping deploy 500 traditional tags during the 2024 season. By sourcing guiding services, lodging and food locally, the project also supports the community of San Carlos.
This collaboration between scientists, anglers and local communities formed the foundation for TBF’s Groundswell Projects, providing a model for community-supported billfish research in other regions.
The project’s reach extends beyond the water. In 2024, the Marlin Fly Project film joined the Fly Fishing Film Tour, sharing the fishery, its community, and the research through more than 300 screenings across 14 countries.
Pop-up satellite archival tags record depth, water temperature and light levels. After a programmed period, they detach, surface and transmit data that researchers use to estimate movements and examine habitat use and survival after release.
Traditional tags complement this work by providing information when tagged fish are recaptured and reported.
Initial findings were presented at the 7th International Billfish Symposium in October 2024. Preliminary data indicated survival after release among tracked striped marlin caught on fly tackle.
Selected tag returns illustrate what this ongoing research is revealing:
An IGFA report covering one deployment in 2024 and one in 2025 documented 90 and 80 days of tracking, respectively. Their estimated tracks extended 1,248 and 813 nautical miles, revealing movements along Mexico’s Pacific coast and into the Gulf of California.
In 2026, a satellite tag deployed by TBF during a Marlin Fly expedition was recovered on a beach in the northern Sea of Cortez after completing its full eight-month deployment.
These returns expand the picture of where striped marlin travel after leaving Magdalena Bay and help guide further research to inform fisheries management, identify important habitats and improve practices for catching and releasing striped marlin.
As part of TBF’s Groundswell Projects, the Marlin Fly Project connects scientific research with the people who know and depend on the fishery. Sponsor a satellite tag or contribute to help continue this mission.
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