The ocean manta rays ( Mobula birostris ) are huge animals that feed on plankton and can reach seven meters in span when they are adults. They usually inhabit tropical and subtropical waters around the world, far from coastal areas, which makes it difficult to access and study their populations. On its basic biology, there are important knowledge gaps, especially when it comes to their youth. Now, in the Gulf of Mexico has been identified the first hatchery of manta rays worldwide, by the Institution of Scripps Oceanography.
Located off the coast of Texas, at the National Garden Ocean Flower Sanctuary of the National Oceanic and Atmospheric Administration (NOAA), the manta ray habitat is the first of its kind described in a scientific study (specifically this appears in the journal Marine Biology). After seven years of studying these marine animals, Joshua Stewart, a doctoral student in marine biology at Scripps and lead author of the study, observed the juvenile blankets while doing research on the population structure of the blankets in Flower Garden Banks, one of the 15 areas submarines federally designated and protected by the Office of National Marine Sanctuaries of the United States.
Working with marine sanctuary personnel, Stewart and his colleagues examined the data from 25 years of immersion log and photo identification compiled by sanctuary research divers. The blankets have unique dot patterns on their bottom that can be used to identify people, just like a human fingerprint.
Using the photographic identifications and observation data, the team determined that about 95% of the blankets that visit Flower Garden Banks are pups that measure, on average, about 2.25 meters in span.
The researchers also compared the habitat use of blankets in the banks with the established criteria to define shark and ray hatchery habitats and determined that the sanctuary is the first confirmed blanket hatchery in the world. Recent genetic evidence indicates that oceanic blankets and a third proposed blanket species ( Mobula cf. birostris ) are present in the banks.