The BBC captured footage of a large gathering, or aggregation of flying rays in the Gulf of California. Because of their jumping out of the water in large packs of hundreds of rays at a time, flying rays (Mobula munkiana) have been a mystery for decades.
Mobula rays are collectively referred to Flying Rays or Flying Mobula, because of their tendency to jump out of the water, sometimes more than two meters while swimming. Mobula rays can be confused with the more popular members of the same subfamily – the Manta Rays.
Oceanographer Joshua Stewart told the BBC that sitting in a boat in the midst of these aggregations is similar to sitting in a pot of popcorn as the kernels explode into the air. Everywhere you look mobulas are jumping out of the water and landing with a loud smack.
Bob Rubin, from the Santa Rosa Junior College in California that these rays often travel in huge schools of thousands of animals and also jump from the water and twist in the air. Bob also noted that he worked in the Gulf of California for many years where there are abundant mobula schools, but he has never seen a mass stranding.
Rubin added that these animals seem to have blood on their “wings” which may have come from slapping something like boats, rocks, sand or maybe even each other. Unless the stomach contents and condition of the gills were examined, it would be impossible to determine a cause of death. However, he said that maybe large underwater noises or electrical signals caused some state of disorientation.
These rays have long, pointed, pectoral fins which they stroke up and down, like wings, for propulsion. On either side of the head and in front of their prominent eyes are two fleshy lobes that project forward to funnel food into their mouth. The tail is long, flattened and spineless and the dorsal fin is small. The upper surface of their body is generally dark purplish to grey, while the underside is white, becoming blue towards the “wings”.
Back in the Gulf of California, Joshua Stewart told that he is worried about the future of the flying rays. While the IUCN only lists the mobula rays as “near threatened” (two steps away from endangered), Stewart worries that the flying ray populations could vanish over time.
He also noted that huge numbers of these animals are moving through relatively constricted geographic areas. Just a few large catches could have dramatic negative impacts on their population.