A new study in Costa Rica has revealed an important difference in how giant manta rays use the ocean. Young manta rays remain close to the Pacific coast, while adults travel hundreds or even thousands of kilometers through international waters. The findings could help scientists better protect one of the ocean’s most recognizable endangered animals.
The research, published yesterday in the scientific journal Frontiers in Fish Science, examined the movements of giant manta rays between 2018 and 2025. Scientists found that shallow coastal waters provide important shelter for younger animals before they are large enough to venture into the open ocean.
The study focused on several locations along Costa Rica’s Pacific coast, including the Murciélago Islands in Guanacaste, the Catalina Islands, Cabo Blanco, Caño Island and Cocos Island, located more than 500 kilometers (310 miles) offshore.
Researchers from Mantas Costa Rica and collaborating marine conservation organizations used electronic tracking devices and underwater photographs to follow the animals. They placed acoustic transmitters on 59 manta rays, tracked 12 individuals using satellite equipment and collected more than 12,000 valid electronic detections.
The results revealed a clear pattern. Younger manta rays tended to remain in relatively shallow coastal waters, while mature animals traveled much farther, often crossing national borders. Scientists believe the younger animals stay close to shore partly because they are more vulnerable to predators, including large sharks and killer whales.
The coastal areas also provide reliable food sources and places where smaller fish remove parasites from the mantas’ bodies.These locations, known as cleaning stations, appear to serve another purpose. Researchers observed that manta rays repeatedly returned to the same areas, suggesting that the reefs are also important gathering places where the animals socialize and engage in courtship behavior.
Jeffry Madrigal-Mesén, the study’s lead author and a researcher with Mantas Costa Rica, said the findings show that manta rays change how they use the ocean as they grow older. Rather than following the same movement patterns throughout their lives, younger animals remain in sheltered areas before expanding their range as adults.
Once fully grown, giant manta rays can reach a wingspan of around seven meters (23 feet) and weigh as much as 2,000 kilograms (4,400 pounds). Their enormous size gives them greater protection from natural predators, allowing them to travel across much larger areas of the Pacific.
The research found that nine of the 12 satellite-tracked manta rays traveled beyond Costa Rican waters. Their movements extended into international waters and the maritime territories of Nicaragua, El Salvador, Honduras and Guatemala. One manta ray traveled approximately 1,832 kilometers (1,138 miles) during a tracking period of just over 40 days, moving from deep waters near Cocos Island toward northern Central America.
These long journeys present a serious challenge for conservation efforts. Although some of Costa Rica’s most important manta ray habitats are located within protected marine areas, the animals often leave those boundaries during their migrations. Once outside protected waters, they may encounter fishing vessels, nets, hooks and heavy boat traffic.
Giant manta rays are particularly vulnerable because they reproduce slowly. Unlike many fish that produce large numbers of offspring, manta rays generally give birth to only one pup at a time, making it difficult for their populations to recover when large numbers are lost. The researchers say protecting individual marine reserves is not enough.
They are calling for greater cooperation among Central American countries to safeguard the ocean routes that connect important feeding, breeding and gathering areas. The findings are also significant for Costa Rica’s tourism industry. Places such as the Catalina Islands, near Playa Flamingo, and the waters around Cocos Island are popular with divers hoping to see large marine animals.
Manta rays are among the most sought-after underwater wildlife sightings, and their presence helps support Costa Rica’s reputation as a destination for marine tourism. However, the same boating activity that brings visitors to these areas can also present risks. Collisions with boats and injuries caused by propellers or fishing lines are among the threats facing the species.
Scientists believe the new tracking information could help authorities identify areas where additional protection, better fishing regulations or changes to boating practices might benefit manta rays. The research also raises the possibility that giant manta rays traveling through Central American waters belong to a distinct regional population. Further genetic studies will be needed to confirm that possibility.
For Costa Rica, the findings provide another reminder of the importance of protecting marine wildlife beyond the boundaries of national parks. Costa Rica’s coastal reefs appear to provide essential habitat for young manta rays, but ensuring their survival as adults may depend on cooperation extending far beyond Costa Rica’s borders.
