Scientists discover world's first known manta ray nursery

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. The manta ray nursery was discovered at the Flower Garden Banks National Marine Sanctuary off the coast of Texas in the Gulf of Mexico.

This is the first habitat of its type to be described in a scientific study. During his research, Stewart observed juvenile mantas while conducting research on manta population structure. Stewart says that the challenge is in observing juvenile manta rays, which is rare. He notes that identifying this area as a nursery helps to highlight the importance of conservation and management.

Manta rays are very large with some adults reaching up to 23-feet wingspans as adults. The massive creatures eat plankton and live in the open ocean. Because aggregation sites are commonly only found far from costal waters, the rays are hard to observe leaving knowledge gaps in basic biology, ecology, and life history.

The researchers also note that baby manta rays are very rare so even less is known about juvenile life stage for the creatures. Stewart and his team dug through 25 years of dive log and photo identification data to see if juvenile manta sightings were common in the area. The data helped Stewart and the team to determine that 95% of the mantas visiting Flower Garden Banks are juveniles with an average wingspan of 7.38-feet.

Flower Garden Banks is a sanctuary for marine life about 100 miles south of Texas with a coral reef ecosystem that is described as far healthier than other reefs in the Caribbean and Gulf of Mexico. The researchers believe that the juvenile mantas are spending time in the relatively shallow banks to recover body temperature after being in the deep, cold waters off the continental slope.

SOURCE: UCSD