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The million dollar mantas

  • Written by  Douglas Seifert
  • Published in Oceans
The million dollar mantas Douglas Seifert
01 Mar
Manta rays have the potential to generate substantial long-term income for many coastal communities around the world. But overfishing in recent years has seen their numbers plummet

Manta rays are always on the move. Unlike the other 500 or so species of layabouts in the ray and skate family – the stingrays, sawfishes and guitarfishes – for mantas, lying on the bottom, blending in with the environment or conserving energy isn’t an option. From the moment they’re born – released free-swimming and autonomous – to the moment they die, three to four decades later if they’re lucky, they must remain constantly, ceaselessly on the move.

Mantas must swim in order to breathe, they must swim to find food and, as ram-jet filter-feeding specialists, they must swim to capture and engulf the small fish and microscopic plankton upon which they feed. They can swim only forward; they have no means to reverse course. Although they can ascend or descend, turn left or right, it’s always with, and as a result of, forward propulsion achieved by undulations of their pectoral fins in the same way that a bird achieves flight by flapping its wings.

Scuba diving and snorkelling enthusiasts the world over actively seek out encounters with manta rays in destinations such as Hawaii, the Maldives, Micronesia, Mexico, the Galapagos and Papua New Guinea. For those fortunate enough to encounter a manta in its natural setting, the impression is almost universal: they are perceived to be majestic animals, graceful, benign, non-threatening, aware, sometimes curious, with the sparkle of intelligence in their wide, unblinking eyes. Indeed, mantas are considered to be among the most intelligent fish in the sea, with the highest brain-to-body-mass ratio of any member of the ray family.

The most popular live-aboard dive boats tailor their cruise itineraries to locations where there is a good likelihood of seeing a manta. Similarly, land-based operations exploit known local manta haunts, getting as many paying tourists to the mantas as they can fit aboard their boats. In some places, such as the tiny Micronesian island of Yap, the allure of diving with manta rays is the lone attraction that sells the package, bringing millions of dollars into the local economy. Manta ray dives on Ningaloo Reef in Western Australia have overtaken whale shark tours as the big-draw money maker for local operators; Bali’s Manta Point at Nusa Penida brings in US$3million a year to local operators.


2011-07-02 at 08-01-22 ReproFishing for manta rays increased significantly during the 1990s. In some cases, modern equipment has enabled a five-fold increase in the number of fish caught



The draw of the manta ray is an inestimable windfall for scuba diving and snorkelling tour operators. And there’s no better example of the financial value of manta encounters to a local economy than the success of Kona, Hawaii. There, the reef manta rays have been studied for more than a decade. Each individual within the resident population has been identified by its characteristic markings and colouration, and the population is known to number around 146.

Kona’s dive and snorkel operators earn a combined US$3.4million a year directly from their manta encounters. Hence, each of the identified 146 mantas currently generates US$23,288 a year. With a lifespan of 40-plus years, each of those mantas will, over the course of its lifetime, generate US$1million in direct revenue from the manta-encounter excursions alone. This amount doesn’t reflect the mantas’ additional value to the local tourism infrastructure by creating a revenue stream for airfares, hotels, rental cars, taxes, restaurants, employment and so on.

From a financial perspective, the manta isn’t just another fish in Hawaiian waters; the ray is an economic benefactor that can legitimately, and accurately, be described as ‘The Million Dollar Manta’. As long as there are mantas, operators can run their boats, pay their staff, cover their overheads and collect their profits, but if the mantas go away, all the operators have left to sell is ‘coral gardens’ and vacant seawater – and that doesn’t add up to much of a business plan.



Mobulids – mantas and their close relatives, the mobula rays – have a broad, thick disc of a body supporting a pair of wide, triangular-shaped, flexible pectoral-fin ‘wings’ and a protuberant head horned by a pair of cephalic lobe fins. Because of this particular anatomy and the fact that they can’t swim backwards, they are prone to entanglement in man-made apparatuses, such as fishing and mooring lines, gill nets and purse seine nets. Hence, they often turn up as incidental fishing bycatch. In the Indian Ocean alone, the reported mobulid bycatch by the tuna purse seine industry exceeds 60 tonnes per year.


MROH07 repoOnce on land, mantas are cut into pieces before their meat and gill rakers are sold


In Mexico, Peru and Indonesia, coastal communities have long hunted mantas and mobulas for their meat on a seasonal or subsistence level. The meat is of poor quality, but hungry bellies forgo gastronomy in favour of survival. Some manta wings are sold in Mexico as a scallop substitute or as a taco filling, but largely, it’s a poor man’s protein.

In the villages of Lamalera and Lamakera, islands across the horizon from each other in Indonesia, the traditional whale-hunting fishermen take mantas and mobulas, as well as whale sharks and mola mola, when they’re unable to catch whales or dolphins. On Lamalera, these artisanal hunters seek out migrating mantas and mobulas from May to October – typically catching around 300 each season.

The meat is dried on bamboo racks, looking like nothing so much as shrivelled, leathery black donuts, and smelling like low tide on a bad day. These dried meat chunks were originally bartered with the inhabitants of other islands for rice, vegetables, fabric and metal, but for some time, they’ve been sold for Indonesian rupiah.



By the late 1990s, the villagers of Lamakera, flush with rupiah from a few good manta harvests, were able to outfit themselves with outboard motors, eschewing the pandanus sails of their neighbours. With greater speed and the ability to hunt farther from land, they were able to kill many more mobulids than in the past. Indeed, during the 2000s, they caught an average 1,500 mantas and mobulas per season.

Mantas and mobulas aren’t designed to have a predator of such dogmatic persistence and unbounded greed. They grow relatively slowly; it takes females between eight and 15 years to reach sexual maturity. A single offspring is produced after a nine-month gestation and females sometimes have punctuated pregnancies, leaving two or three years between offspring.

Unsurprisingly, the boats are now returning with fewer mantas and mobulas than they did in the past, and the manta harvest requires more and more effort and expense. But the Lamakerans continue their hunt, for not so long ago, Chinese traders from Jakarta and Surabaya began paying them a great deal more money than they were used to receiving for dried manta meat. The traders paid them more than five times as much – not for the mantas’ flesh, but for their gill rakers.



The Chinese dried seafood market drives the fishing industries of many developing countries. These fisheries can’t compete with the developed-world fishing fleets for top-price markets that demand fresh and flash-frozen seafood. Instead, slow, marginally seaworthy subsistence boats, manned by illiterate and unskilled labourers, go on long-duration voyages, dehydrating the prized parts of their catch on wooden decks under the tropical sun.


MROH11 reproChinese medicine has a 2000-year history, but manta ray gill rakers have only recently appeared on menus. They are said to offer benefits to the blood and liver, to remove toxins and bolster the immune system


One segment of the dried-seafood business is devoted to fulfilling gourmet ingredients for Chinese gastronomy, such as sea cucumber for sauces and shark fins for soup; the other segment is the traditional Chinese medicine market, where dried seafood joins other desiccated plunder from the natural world – rhino horn, tiger penis and the like.

Traditional Chinese medicine has a 2,000-year history, but manta ray gill rakers have only appeared as an ingredient in the past decade, as a new generation of entrepreneurs has pushed them as a miraculous ingredient of a cleansing tonic or soup. Vendors spin a tale of the gills’ incredible properties, drawing analogies between the filtering of seawater and the filtering out of pollutants. The gill rakers are said to offer benefits to the blood and liver, removing toxins and bolstering the immune system.

So new are the manta ray gill rakers to the traditional Chinese medicine market that many traders don’t even label them as such. Often, they are referred to simply as peng yu sai, or ‘fish gills’.



The epicentre of the manta gill raker industry is Guangzhou, China. It’s here that 99 per cent of manta ray gill rakers come to be sold at their highest wholesale market price – roughly US$250 per kilogram for large gill rakers, and US$133 per kilogram for small ones. Based on the average estimate of around 60,000 kilograms of gill rakers traded annually, the total retail market for gill rakers is projected to be worth US$11million per year.


MROH12 REPRO2Dried gill rakers can fetch up to US$250 per kilo in traditional medicine shops in China


This commercial fishery specifically targeting manta and mobula rays has rapidly come into existence, flourished and expanded with alarming efficiency. In the tropical waters of the Indian Ocean off India and Sri Lanka, fishermen land more than 79,000 mobulas per year, while in the Indo-Pacific off Indonesia and the Philippines, tens of thousands more mantas and mobulas will find their way to fish markets, and eventually their gill rakers will make their way to China.

A manta in a fish market sells for US$40–500, depending on the size of the animal and the weight of its gill rakers. If that same animal, swimming off the coast of Hawaii, Bali or the Maldives, isn’t killed, it could provide a livelihood that’s potentially worth millions of dollars for local people, as well as a legacy for future generations.



The two species of manta ray are listed on the IUCN Red List of Threatened Species as vulnerable globally. At present, they’re only formally protected in New Zealand, Ecuador, the USA, Guam, Maldives, Yap, Indonesia, the Philippines and Mexico.

In November 2011, the oceanic manta ray became the first ray to be listed on the Convention on Migratory Species, which obligates signatories (currently numbering 116) to strictly protect the animals, conserve and restore their habitats, mitigate obstacles to their migration, and control other factors that might endanger them. But mantas can migrate across large distances, so they’re still vulnerable to being fished as they roam. And the reef manta is still unprotected.

Brazil, Colombia and Ecuador have now submitted a proposal to include the genus Manta in Appendix II of the Convention on International Trade in Endangered Species (CITES). The proposal will be considered in March at the 16th meeting of the Conference of the Parties.

It’s clear from recent assessments that populations are severely depleted and that international trade is driving the declines. Over the past seven years, the number of mantas caught has increased nearly fourfold, with an estimated 30 per cent drop in global populations. An Appendix II listing would regulate international trade to ensure that it’s sustainable and legal, and would thus help populations to recover from decline. Without that protection, the future of this graceful, restless ocean denizen looks very bleak indeed.


To learn more and get involved, visit www.mantatrust.org and www.sharksavers.org

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