Dolphins in the Everglades: Meet ForEverglades Fellow João Valle-Pereira
Updated: 2 days ago
September 14, 2026
Florida Bay is home to remarkable species, but few behaviors are as fascinating as the "mud ring feeding" tactic performed by some bottlenose dolphins. João Valle-Pereira, a graduate student at Oregon State University and the 2026 Micky and Madeleine Arison Family Foundation ForEverglades Fellow, is studying this unique foraging behavior and what it reveals about the health of Florida Bay's ecosystem.
Florida Bay: A Vital Piece of the Everglades
Florida Bay sits at the southern tip of the Everglades ecosystem, bordered largely by Everglades National Park. As the estuary where freshwater from the Everglades meets the ocean, Florida Bay's health is directly tied to the quantity, timing, and distribution of freshwater flowing through the greater Everglades system. That makes it not just a haven for marine life like bottlenose dolphins, but also a critical indicator of how well Everglades restoration efforts are working downstream.
What Is Mud Ring Feeding?
Mud ring feeding is a highly specialized foraging tactic performed by certain bottlenose dolphins in Florida Bay's shallow waters. To execute it, a dolphin slaps its tail against the seafloor, stirring up sediment that forms a ring of mud around a school of fish. As the ring closes in, the fish, trying to escape, leap out of the water directly into the dolphin's waiting, open mouth
"It's an interesting feeding or foraging tactic," João explains. "They slap their tails on the bottom of the ocean. They create this mud sediment looking like a ring. And as this mud ring closes, the fish jump out of the water and the dolphins stay with their mouths open, waiting for the fish to jump."
Because this tactic requires shallow water to be effective, it only occurs in specific areas of Florida Bay, making it an ideal behavior to study when trying to understand habitat use and the ecological needs of this dolphin population.
From Historical Data to the Field
João's research began well before he visited Florida Bay. Using historical data from collaborators and satellite imagery, his team was able to identify traces of mud ring feeding and pinpoint likely locations where the behavior was occurring.
With support from The Everglades Foundation’s ForEverglades Research Enhancement Grant and the Micky and Madeleine Arison Family Foundation, João and his team have taken this research a step further, heading out into the field to ground-truth their findings and study the behavior firsthand.
To do this, the team collects data across four key areas:
Photo identification – Documenting individual dolphins to determine which ones perform the mud ring tactic most frequently, helping identify key "knowledge-holders" within the population.
Overhead video – Captured using a camera mounted on a tall pole, this footage allows the team to understand how many dolphins participate, how much fish they catch, and the size and speed of each mud ring.
Bioacoustics – Using a hydrophone, the team measures the acoustic signature of the tactic to understand how much energy and investment dolphins put into each feeding event.
Environmental data – Measurements like water quality and salinity help identify the ideal environmental conditions under which mud ring feeding occurs.
Researchers studying Bottlenose Dolphins in the Florida Bay Researchers studying Bottlenose Dolphins
Photo on the left by João Valle-Pereira. Photo on the right by Steve McCulloch
Why It Matters for Conservation
Understanding this behavior has implications for conservation and policy.
“Informing effective conservation strategies requires understanding three things: where dolphins perform this tactic, who the key individuals are that carry this specialized knowledge, and how they execute it,” says João.
By identifying the specific shallow-water habitats and environmental conditions dolphins rely on for mud ring feeding, and other habitat needs, João's research provides a more holistic picture to help protect this population and the broader Florida Bay ecosystem they depend on. Because Florida Bay is so closely tied to freshwater flows from the Everglades, this work also helps illustrate how restoration efforts ripple outward to affect wildlife far beyond the marshes and sawgrass most commonly associated with the Everglades.
Photo on the right by Steve McCulloch
Supporting the Next Generation of Everglades Scientists
João's fieldwork is made possible through The Everglades Foundation's ForEverglades Research Enhancement Grant Program. Since 2008, the program has awarded more than $2.3 million to 111 master's and doctoral students, supporting outstanding graduate research related to the current and future restored Everglades ecosystem. Many past recipients have gone on to become leading scientists and conservation leaders in their fields.
João's fellowship is generously supported by the Micky and Madeleine Arison Family Foundation, part of the Foundation's 25-26 Fellowship class, helping to ensure that critical research like his continues to inform how we protect and restore this one-of-a-kind ecosystem.
This project is a collaboration between LABIRINTO, at Oregon State University; the Marine Conservation Ecology Lab at FIU; the Geospatial Ecology of Marine Megafauna Lab at OSU; and Protect Marine Wildlife, based in Key Largo.
Watch the video below to see João and his team in the field, documenting this remarkable behavior firsthand in the waters of Florida Bay.
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