Scientists discover world’s first known manta ray nursery

Rodiano Bonacci
Giugno 20, 2018

The researchers also note that baby manta rays are very rare so even less is known about juvenile life stage for the creatures. However, known aggregation sites are usually far from coastal areas, which makes these fish hard to study - and juveniles are nearly completely absent from manta ray populations. "This discovery is a major advancement in our understanding of the species and the importance of different habitats throughout their lives".

A group of researchers led by Ph.D. candidate Joshua Stewart from Scripps Institution of Oceanography at the University of California San Diego and scientists from the NOAA Office of National Marine Sanctuaries have discovered what they say is the first known manta ray nursery in the world.

After Stewart observed multiple small mantas, he checked with the sanctuary staff to see if such sightings were common.

Luckily, Flower Garden Banks is now looking at expansion and hopes to add additional reefs and banks in the Gulf of Mexico to its 56 square miles, which were first protected in 1992.

"This is exciting news for the manta rays in the northwestern Gulf of Mexico", said George P. Schmahl, superintendent of the sanctuary.

Flower Garden Banks is a pristine sanctuary about 100 miles south of Texas that harbors coral reef ecosystems that have remained far healthier than other reefs in the Caribbean and Gulf of Mexico. These coral communities have grown on top of hard substrate thrust out of the seafloor by the development of salt domes.

Scientists believe the younger rays return to the banks to warm up after diving into deeper, colder waters to search for zooplankton, according to the release. Catching sun at the water's surface could be too risky, as several large shark species dwell in the Gulf. "They might be hanging around the banks because it could be a little safer than open water". They found that roughly 95 percent of the mantas visiting Flower Garden Banks were juveniles. Manta rays are threatened globally by targeted fisheries and bycatch. In the case of the giant manta rays, they have already been listed as threatened species under the U.S. Endangered Species Act 2018.

The Flower Garden Banks is one of the 14 federally designated underwater spots under NOAA's protection and is the only site of its kind in the Gulf of Mexico.

Female manta at Flower Garden Banks National Marine Sanctuary.

"Nowhere else in the world has a manta ray nursery area been recognized-which heightens the importance of the sanctuary for these pelagic species", said Schmahl.

Sanctuary officials say they intend to widen the protected area by adding more reefs and banks in the Gulf known to be home to manta rays.

"The juvenile life stage for oceanic mantas has been a bit of a black box for us, since we're so rarely able to observe them", said Stewart. "From a conservation perspective, it means that a lot of the questions that you get to answer will actually be meaningful and have an impact on management".

Flower Garden Banks has been pursuing a plan to increase the protected areas within the sanctuary since 2006, Emma Hickerson, the sanctuary's research coordinator, told Live Science.

Altre relazioniGrafFiotech

Discuti questo articolo

Segui i nostri GIORNALE