bentfin devil ray

10/31/2018

A Bentfin Devilray, Mobula thurstoni. Source: Australian National Fish Collection, CSIRO.

Happy Halloween! Let's learn a little bit about the devil... the bentfin devil ray (Mobula thurstoni) that is. This large ray can get up to 180 cm in disc width (DW) according to the IUCN. They are found in tropical and subtropical waters worldwide both in the shallows (<100 m depth) and offshore pelagic waters. #Finfact: Devil rays are quite sensitive to even moderate levels of fishing pressure due to their low reproductive rates (they usually only have one pup per year) and low post-release survival. Scary!

Bentfin Devilrays, Mobula thurstonion the outer Great Barrier Reef, Queensland, August 2017. Source: mattytestoni / iNaturalist.org.

What kind of fishing pressure are we talking about? Gill plates, actually. "What the...?" You see, there is increasing pressure on these animals because the international trade in gill plates has led to largely unregulated and unmonitored fisheries worldwide. Manta ray gill plates are declining, so devil ray gill plate demand is increasing to make up for the loss. In fact, this pressure is the reason for their recent CITES Appendix II listing! The bentfin devil ray is also taken as bycatch in gillnet, purse seine, and longline fisheries in the Pacific, Indian, and Atlantic Oceans, which are part of their range. These animals are also targeted in Peru, the Philippines, Mexico, India, Myanmar, Sri Lanka, and Indonesia for their meat and gill plates.

Also known as the "Lesser Devil Ray," "Smoothtail Devil Ray," "Smoothtail Mobula," or "Thurton’s Devil Ray" in English, we especially love the moniker it has in French (Mante Vampire) and some in Spanish (Chupasangre, Chupa Sangre, Diablo Chupasangre). Basically 'blood sucker' or 'vampire ray.' We like it... and how appropriate for Halloween!

Due to this increased fishing pressure, the IUCN has assessed them as Near Threatened (NT).

WHAT DID YOU LEARN ABOUT THIS ANIMAL?

GLOSSARY

Bycatch: The part of a fishery’s catch that is made up of non-target species.
Endemic: Native to a specific region or environment and not occurring naturally anywhere else.
IUCN: International Union for Conservation of Nature.
Trawl fisheries: Fisheries that pull a fishing net through the water behind one or more boats.