On the beaches of the east coast of Florida, a few meters from the shore, a discreet but essential form circulates beneath the surface: the Atlantic manta ray Mobula yarae. Long ignored in conservation programs, this recently recognized species now appears to be a key player in coastal marine dynamics. A study carried out jointly by the University of Miami (Rosenstiel School of Marine, Atmospheric, and Earth Science) and the Marine Megafauna Foundation, published in December 2025 in the journal Marine Biology, reveals that these juvenile rays harbor, on their own bodies, entire communities of fish.
These stable and structured associations, far from being anecdotal, suggest that manta rays serve as truly mobile habitats. Understanding how these interactions work becomes crucial in a context of increased human pressure on coastlines and progressive collapse of marine biodiversity.
An ecological role that has long been underestimated
Manta rays have long been perceived as simple planktivorous filter feeders. They sail slowly in tropical and subtropical seas. However, the recent study reveals that these animals — particularly juveniles of the species Mobula yarae — play a much more active role in coastal ecosystems. This role is based on complex and hitherto poorly documented interactions. The manta ray acts as a mobile habitat for other fish.
Out of 465 observations conducted between 2016 and 2024 off the coast of Florida, each juvenile manta ray was accompanied by at least one fish. These associations are not exceptional, but a regular and structured behavior observed throughout the year. These interactions constitute a form of symbiosis, in the broad sense, bringing together relationships of commensalism, mutualism and sometimes even opportunistic predation.
The specificity of the study is to focus on Mobula yaraerecently reclassified species, genetically distinct from its Indo-Pacific cousins. These rays live in very coastal waters — often less than a kilometer from the shore — and at depths of between 0.5 and 15 meters. This proximity to the coast exposes them to direct human pressure. But it also offers an exceptional observation window for scientists.
Understanding what a manta ray represents for its immediate environment means rethinking its status. More than a species to be protected, it becomes a structuring vector of local biodiversity. The study suggests that its ecological role is comparable to that of a temporary moving reef. It transports entire communities to otherwise structure-poor areas.
A biological architecture serving biodiversity
Detailed analysis of the videos captured by the researchers shows that the fish that accompany the manta rays do not do so randomly. They form specific aggregates, mainly composed of teleost fish belonging to four groups: Echeneidae (remoras), Decapterus spp., Rachycentridae (notably cobias), and other Carangidae.
© Yeager, EA, et al., 2025
Mobula yarae with different symbiotic fish observed between 2023 and 2024.
Remoras, or sucking fish, remain the most frequently observed. Their unique anatomy, notably their dorsal fin modified into an adhesive disc, allows them to attach permanently to their host, often on the ventral side, around the eyes or the gills. In 42% of cases, the symbionts localized to specific functional areas, which suggests adaptive behavior. Decapterus prefer the rear flanks of the ray, while cobias appear more sporadically. The latter seem associated with less frequent, but potentially targeted, interactions.
On average, each ray is accompanied by six individuals, although some groups reach up to 230 fish. These aggregates vary depending on the season. Remoras appear more numerous in the dry season (November-April), while non-Decapterus trevally appear mainly in the wet season. According to the researchers, this structure is not trivial. The diversity of species present increases the total size of the aggregate. This reinforces the hypothesis of shared housing.
The ecology of these interactions shows that the manta ray does not only serve as a transport platform. But also a place of feeding, resting or reproduction. Some species take advantage of the movement of the ray to hunt more effectively. While others feed on parasites or the remains of filtered plankton. These behaviors reveal ecological interdependence. The ray acts as a central organism, structuring a network of multiple interactions.
Durable, non-random interactions
One of the major contributions of the study lies in the detailed analysis of the stability of the aggregates over time. Four manta rays, identified visually and monitored for several years, were observed more than ten times. For two of them, the researchers noted a stable composition of the symbionts, in particular for the remoras, present at each observation.
This stability was measured using the Bray–Curtis similarity index. It makes it possible to evaluate the constancy of a biological community. In certain rays, this index indicated a similarity greater than 80% between two consecutive observations. This means that the same species, and possibly the same individuals, accompanied the stingray over time. Emily Yeager notes that some remoras were recognized by their size, position, and even visible markings.
This familiarity between host and symbionts evokes more complex relationships than simple opportunistic associations. Similar behaviors have already been observed in other marine species, such as dolphins and whale sharks. Symbionts can follow their host over long distances or through significant variations in temperature and depth, sometimes to the detriment of their own thermal comfort. This fidelity could be explained by reproductive or nutritional benefits obtained only from a given host. In addition, the scarcity of structures in the sandy areas where these rays live makes this proximity even more valuable.
Conservation issues and implications for maritime policies
The ecological role of juvenile manta rays revealed by this study poses direct conservation questions. In Florida, coastal waters are high-use areas: boating, recreational fishing, water sports. However, these activities often take place in the immediate vicinity of known habitats of Mobula yarae. The authors warn of the risks of collisions with boats, entanglements in fishing lines, and even indirect targeting by fishermen of cobia, a species frequently observed in association with rays.
Jessica Pate, co-author, emphasizes this fact in a press release. “ Slowing down boat speeds in areas identified as breeding grounds for rays is a simple but essential measure. “. These areas are well known to scientists: shallow, sandy, less than a kilometer from the shore. This is where the density of juvenile rays is highest.
Another issue lies in the management of targeted fisheries. In some areas of Florida, fishermen intentionally use the presence of manta rays to locate cobia. This practice raises the risk of accidental injury to rays and interruption of their ecological interactions. However, cobias themselves are the subject of worrying fisheries monitoring. Their population is showing a decline, classified as overfished according to local authorities (SEDAR 2020).
The implications of these discoveries go beyond just protecting a charismatic species. They require consideration of interspecific interactions in the management of coastal areas. Integrating the manta ray as a structuring element of ecosystems leads to a review of priorities. It is not only the animal that must be protected, but the ecological role it plays for an entire marine community.
Source: Yeager, EA, Pate, J., Saltzman, J. et al. “Stability and spatial variance of Mobula yarae-associated fish aggregates in South Florida”. Mar Biol 17316 (2026).
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
