Mantas & Stingrays

A quick pass into view.

Enigmatic world of shark and ray behaviour unveiled

Elasmobranchs have become lucrative targets with the depletion of traditional fish stocks and the surge in the shark fin trade. Although, in recent decades, much scientific evidence has challenged traditional misconceptions, stereotyped media portrayals persist, and they hinder conservation efforts. So, this special issue was created to highlight the complex behaviour and cognition of sharks and rays.

Tiger shark
Tiger shark

Shark and ray populations in Northwestern Atlantic are recovering

The shark and ray population in the north Atlantic are in recovery, according to a recent study published in the Proceedings of the National Academy of Sciences (PNAS) journal.

Lead author Nathan Pacoureau, postdoctoral research fellow at Simon Fraser University (SFU), and his team came to this conclusion after analyzing trends in fishing pressure, fisheries management and population status for wide-ranging coastal sharks and rays in the western Atlantic Ocean. 

A manta ray near Isla de la Plata off the coast of Ecuador. Photo courtesy Fundacion Megafauna Marina del Ecuador.
A manta ray near Isla de la Plata off the coast of Ecuador

Largest known manta ray population is thriving off the coast of Ecuador

Although manta rays are readily capable of long-distance movements of hundreds if not thousands of kilometres, most populations appear to be philopatric (tending to return to or remain near a particular site or area—ed.) with few examples of long-distance dispersal.

Oceanic manta rays, the largest ray species, were listed as threatened under the U.S. Endangered Species Act in 2018. In 2019, their threat category increased from vulnerable to endangered on the International Union for the Conservation of Nature’s Red List.

Sorting out the Stingrays

The bluespotted ribbontail ray is easy to distinguish from other small rays with blue spots by its oval shape. This one was found sheltering under a wreck in the Red Sea. Photo by Nigel Marsh.

Gliding slowly over the rocky reef, I was mesmerised, watching all the colourful reef fishes going about their daily activities. I was so entranced that I was startled to look up and find I was on a collision course with a massive stingray. This was the first stingray I had ever seen, and the giant creature terrified me. In the second it took my panicking brain to work out what to do, the stingray suddenly saw me and also got a shock.

Giant manta ray. Photo by Scott Bennett
Giant manta ray

How big is it? Drones assisting in manta ray research

A global breakthrough in recording manta ray information has been made by an Auckland University doctoral candidate. In a study entitled “How Big Is That Manta Ray?” published in Drones, Edy Setyawan outlined how a drone camera, with the addition of a PVC pipe in the ocean, can be utilised to accurately measure the world’s largest ray species. “I could see that from the drone there was some size variation, some mantas, they are bigger than the others,” said Setyawan. “It’s quite cheap using a small drone, but it can give us a big impact on manta ray conservation.”

Stingrays' bulging eyes makes them more streamlined

Stingrays have a higher swimming efficiency than most other aquatic animals, and many studies regarding high-performance swimming have focused on the hydrodynamic benefits of stingrays swimming styles: “Rajiform” locomotion (undulation) and “mobuliform” locomotion (flapping), which are considered the key to stingrays' high-performance swimming.