When people think of sharks, they typically think of the charismatic creatures featured on Shark Week. However, there are over 500 species of sharks – ranging from the obscure cookie cutter shark to the massive whale shark. And, sharks have very close cousins, the rays and skates, all of whom are in the same elasmobranches family, which is why many scientists group all three when referring to them as "sharks, skates and rays."
It is understandable how one might overlook the issues facing several species of rays – which are hauntingly similar to those facing their toothy cousins – not realizing they are in the same family classification. What's worse, it is incredibly easy to do, as very little actually exists on the subject. One has to dig deep on the Internet to pull the full picture together. It seems, with all the attention sharks have gotten, we have collectively forgotten about their magnificent close cousins – the rays.
All over the world, many species of rays face local fishing pressures and are the common bycatch casualties to indiscriminate fishing methods – just like sharks. In European waters, particularly the Mediterranean, the giant devil ray is classified by the International Union for the Conservation of Nature (IUCN) as endangered. And, the large skates, found in UK waters, have been exploited for decades, leading to alarming declines, with the common skate now listed as critically endangered.
But, it was not until recently, however, many conservationists realized how closely the two lineages were tied together in the extinction trade business. Growing demand for the manta ray, the ocean's gentle giant, and its close cousin the devil ray, in part thanks to the loss of regional sharks, has transformed subsistence and localized ray fishing into a global, commercialized, export operation. For instance, in the small eastern Indonesian port of Lamakera, catches of manta have exploded in a few short years from a few hundred to several thousand per year. Anecdotally, mantas are now reported to be rare in the Philippines, a place where they once thrived, especially around the Bohol Sea where a major manta fishery was centered. And now, mantas face a potential future shared by hammerheads, whites, and bull sharks: extinction.
Why would someone target an animal as beautiful, harmless, and intelligent as a manta whose brain to body mass ratio is one of the highest in the sea? How could someone harvest these creatures that have become adored by anyone who has ever encountered one? For greed-fueled by skyrocketing consumer demand. Just like sharks.
In Indonesia, India, Sri Lanka, Mexico, Japan, and the Philippines, mass fisheries are feeding the surging demand for manta and devil ray meat, cartilage, and gills. And with their value dramatically increased, mantas everywhere, particularly in Southeast Asia, are under attack, threatening local populations worldwide with a very real, impending regional extinction.
Not only are mantas and mobulas targeted for their meat, skin, and cartilage – and are even used as a shark fin soup filler, their cartilage mixed with low-grade shark fin for cheaper versions of the soup – but they are also targeted for use in alternative eastern medicines. The rays' branchial gill plates, which filter plankton from seawater allowing the manta to eat, and constitute a small percentage of the animal's weight (just like shark fin), are highly sought after. And, it is this demand that is most devastating for these rays. Fishing fleets are hunting mantas globally from Mozambique to Brazil to Sri Lanka, just for their gill rakers.
Although no scientific evidence exists to support any claims, Chinese practitioners believe the consumption of gill rakers – called peng yu sai – help reduce toxins in the blood by purifying and cooling it, reducing body temperature and aiding blood circulation. Its surge in popularity is making dried and ground gill rakers even more valuable than shark fin. And, as shark fin becomes harder to find, rakers are even being offered as an alternative, increasing demand further.
In another similarity to sharks, the life history of manta rays makes them highly susceptible to overfishing – even more so than some of their cousins. A single fishing fleet can easily wipe out a local manta population in weeks or months, with little chance of rebound given their slow reproduction, limited local populations, and lack of migration (at least for the reef species).
No international laws and only a handful of national laws exist to prevent this impending disaster, as mantas are only protected in five small areas in the world (Maldives, the State of Hawaii, the island of Yap, the Revillagigedo biosphere (in Mexico), and the Yaeyama Islands, Japan, though there is evidence illegal fishing still occurs.
And, we still know so little about mantas – in fact, a new species was discovered just last year. It is hard to believe we may lose this animal prior to truly understanding them, their significance to our planet, and the important things they (and the secrets their evolution holds) have to teach us.
In 2004, manta rays were identified by CITES as a species associated with severe depletion and the IUCN red lists mantas as "near threatened". However, regionally, it is clear we are losing our mantas, and that the trade is following the same pattern of shark fin business – undoubtedly with many of the same players involved. That is the thing with the extinction trade business. They move from one species to the next – until they are all gone.
Without urgent intervention, protection, and increased awareness and understanding, another magnificent ocean creature may silently disappear before our collective eyes.