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First known manta ray nursery in Florida and new species news!

By Dave Armstrong - 20 Jun 2018 8:35:0 GMT
First known manta ray nursery in Florida and new species news!

The oceanic manta, Manta birostris has been decimated around Sri Lanka and the South China Sea, but can be a literally-huge tourist attraction. Here this beauty is photographed at Hin Daeng (Thailand) but the Maldives and Seychelles provide other opportunities to the numerous manta enthusiasts. Most individuals have names (we don’t yet know this one), as there aren’t many produced with a long gestation and single pups! Oceanic manta ray image; Credit: © Jon Hanson, Creative Commons Attribution

Despite recent claims, Wayag Lagoon in Raja Ampat, Indonesia was the first location found for the young of Manta birostris, the great oceanic manta ray. Here is a scientific paper however, which clearly presents the first proper evidence: Joshua D Stewart of Scripps and the Manta Trust is the lead author, with 3 co-authors from the NOAA reserve, based in Texas.

Now the NW Gulf of Mexico could supercede that earlier discovery, if the Scripps Institution of Oceanography research can now be extended. We somehow need to find out what happens to these juvenile rays that are so rare elsewhere in the world’s oceans. Nobody is able so far to actually study the early juveniles and the actual birth. While big mantas can be friendly, the young are far too often caught in fishing nets to be careless around humans, and deep waters probably hide them from both predation and human investigation.

The 56 miles2 (145 metres2) , and expanding, reserve in NOAA's Flower Garden Banks National Marine Sanctuary consists of healthy coral reefs, which are rare in the Caribbean these days. Bleaching has taken place several times, but the corals remain living on most occasions. Deep water off the reefs provides a refuge and an upsurge of suitable planktonic food for the animals. Josh Stewart has looked into the 25 years of records since the reserve was formed. Predators include large surface-living shark species, but they are less frequent than in the southern Caribbean, where the Atlantic brings currents around all the major islands and other common rays such as the eagle rays and mobulas could easily be mistaken for juvenile mantas. Oil pollution is a major problem in the Gulf, too, as we have often seen in the past.

Josh Stewart has been collecting DNA samples in addition to his nursery work. Hopefully the relationships of the mantas within the Gulf of Mexico and those that come from the western Atlantic can be worked out. Then we can tell where species and/or subspecies exist. For those wondering why mantas are endangered (American Federal rules) and Vulnerable worldwide (IUCN), this is our article to explain why the gill rakers are mistakenly applied to the beliefs of ancient Chinese medicine!