Marine Species: Sicklefin Devil Ray

 

The sicklefin devil ray is one of the lesser-known mobula species. Where can you see these rays on a dive?

What is a devil ray?

One of the lesser-known mobula species, the sicklefin devil ray, also known as the Chilean devil ray or spiny mobula, can reach a disc width of up to 12 feet (3.7 m). Their striking frontal horns, not dissimilar to the frontal lobes of manta rays, are to thank for the name “devil ray,” and they’re thought to resemble the devil’s horns.

Females are bigger than males, and only the left ovary is functional. They deliver only one pup at a time and size at birth is around 4 feet long (118 to 132 cm).

Green on the top of their bodies and white on the bottom, sicklefin devil rays are often accompanied by two remoras. They often swim close to oceanic manta rays as well, and can dive quite deep when searching for prey. Scientists have observed these creatures diving to nearly 6,500 feet (2,000 m), which makes them one of the ocean’s deepest diving animals. The rays can dive to such great depths thanks to a complex network of blood vessels that surround their brain. These enable the brain to stay functional and at an optimal temperature when diving to great and cold depths.

The sicklefin devil ray, as well as other species of mobula and manta, display high degrees of social interactions and curiosity toward humans, which makes them a pleasure to dive with.

Where can you find devil rays?

Mobulas are long migrators, usually traveling great distances in summer and winter to search for food. Sicklefin devil rays inhabit most tropical and temperate waters around the world, but the Azores Islands in the Mid-Atlantic are one of the best areas to observe mass congregations. On Princess Alice Bank, 50 nautical miles (93 km) off the coast of Pico Island, divers have encountered over 80 individuals in one tight group.

Are they threatened?

The IUCN Red List classifies sicklefin devil rays as vulnerable due to the high demand for their gill rakers. While locals often consume the meat from the fished rays, the catalyst for the dramatic increase in hunting rays are the animal’s gill rakers, which are dried and exported for the Asian medicinal market. Dried gill rakers are also crushed into a powder, often added to soup and broth. Fishing nets and boat traffic also present problems for devil rays, as they become entangled as bycatch or fall victim to boats when they surface.

 

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