A Year in the Life of Larry the Whale Shark

On May 28, 2025, researchers set out from Boca Ciega Bay, Florida, heading into the Gulf of America aboard a 36-foot vessel owned by physician Dr. Larry Spetka. Dr. Spetka graciously hosted the team as they searched for whale sharks recently spotted near Tampa Bay. Their goal: find and tag whale sharks to track their movements and migratory patterns in the Gulf and beyond.

Thanks to sighting reports from local anglers to the University of Southern Mississippi's whale shark reporting form , the team quickly located a sizable group of sharks. Whale sharks are the largest fish in the ocean, but there aren't very many of them, so scientists rely on sightings reports from the public to find and study them.

"Citizen scientists are a critical part of the research we conduct. We cannot be on the water all the time, so when the public reports their sightings, they are helping us glean knowledge on whale shark behavior and movements," said Jill Hendon, director of the Center for Fisheries Research and Development at The University of Southern Mississippi and co-lead on this project.

Uncovering a Culinary Clue: the Egg Buffet

As the team donned snorkel gear and slipped into the water, the first thing they noticed was all the fish eggs in the water. The scientists believe this is what the whale sharks were here for-a buffet of fresh fish eggs.

"There were so many eggs in the water it was almost hard to see the sharks," recalled Dr. Eric Hoffmayer, NOAA fishery biologist and co-lead on the project. "Based on what we previously knew about whale shark feeding, and the timing of fish spawning, we had a theory about what species the eggs were from but decided to collect samples to confirm."

After sending the eggs off for genetic sampling, the team learned they were from a species previously undocumented as a whale shark food source in the Gulf of America. In past years, whale sharks were observed feeding on the eggs of little tunny-also called false albacore or bonita. This time, the eggs were from Spanish sardines. This uncovered a new clue about whale shark diets, and which prey species may be influencing their distribution and movements.

Start of the Journey: Attaching the Satellite Tags

The researchers used specialized, removable clamps to attach satellite tags to the sharks' dorsal fins. Satellite tags can stay affixed to marine animals for nearly 500 days, and send location data back to scientists in the lab via satellites. While they successfully tagged multiple individuals, one 26-foot male-named "Larry" in honor of Dr. Spetka-would go on to provide an extraordinary amount of data. At the time, the team had no idea just how significant Larry's upcoming journey would be.

Reflecting on the mission, Dr. Spetka noted, "Nothing humbles a physician quite like standing beside real scientists on a whale shark tagging expedition-suddenly your white coat feels a lot less impressive next to people who can find, track, and understand a 40-foot fish in the open ocean."

Following the Loop Current: Larry's Epic Year of Data

Larry's satellite tag has transmitted his location for nearly every day since being deployed, resulting in more than 6,200 data points. Larry continues to "ping" almost every day, offering a wealth of information on movement and behavior.

His travels have been extensive:

• Headed south to the Dry Tortugas near the Florida Keys
• Returned to Tampa Bay, where our researchers saw him again in June
• Traveled to Cuba and Honduras by September, then ventured over to the western Gulf for the winter
• Followed the edge of the Loop Current (visible by the orange warm water in this sea surface temperature map) around the Gulf, likely feeding on plankton

Currently, Larry is offshore of Homosassa, Florida, and the team hopes to encounter him again this year

Tracking a whale shark for a full year has provided valuable insights into whale shark biology, behavior, and regional conservation needs. This journey has already pointed researchers toward potential foraging grounds across the Gulf. By showing how whale sharks interact with the ocean day after day, these long-term datasets help us better understand the environmental drivers that guide these animals.

While satellite tags can last up to 500 days, many of them last only one-third that long due to tag damage or other complications. This tag is pushing the boundaries of data collection with a year of data! The team is eager to uncover more from this shark's trek.

The Bigger Picture: What We've Learned

Larry's journey is just one piece of the puzzle. The research team has tagged 15 whale sharks during this project, and is looking for more tagging opportunities this season. While this particular shark's journey has been fascinating, it's important to gather data from multiple individuals to paint a clearer picture of whale shark movements across their population.

What the Tags Told Us So Far

One of the 12 known predictable whale shark aggregation sites in the world was historically located at Ewing Bank, Louisiana. While we are no longer seeing whale sharks routinely at this site, they remain present in the Gulf of America. We are currently investigating whether this absence is the result of a regional distribution shift, a population change, or a behavioral modification.

Our current research documented whale shark feeding aggregations of up to 19 sharks offshore of Tampa Bay, Florida, targeting Spanish sardine eggs. We have also identified another potential feeding area north of the Dry Tortugas, Florida, though more research is needed to understand its seasonal importance.

Our recent findings have shown that whale sharks spend 40 to 60 percent of their time in the top 10 meters of the water column. This prolonged use of the surface waters puts them at risk for interactions with vessels in high-traffic areas.

Partnership and Public Involvement

This project is a collaboration between The University of Southern Mississippi Center for Fisheries Research and Development , NOAA Fisheries, and the Blue World Research Institute . Supported by the Bureau of Ocean Energy Management, the study aims to gain deeper insights into the behavior and migratory patterns of whale sharks in the Gulf. This project has also been successful due to the contributions of the Florida Fish and Wildlife Research Institute.

"Whale sharks are a species with a global distribution. It is imperative that we scientists work together to better understand these highly migratory animals," said Hendon. "This collaboration in the Gulf of America has been invaluable in helping us understand how whale sharks are using Gulf waters. We also take this information to collaborate with international partners to understand how the Gulf animals fit into the larger global distribution."

If you spot whale sharks out in the water, please help support our research by reporting the sighting at bit.ly/whale-shark-report .