Manta rays are arguably the most majestic creatures in the sea. (Although I might be slightly biased, as I’ve had a fascination with these gentle giants since I started scuba diving a few years ago.) It was a big dream of mine to swim/dive with the Mantas, so when we landed in Bali I couldn’t resist traveling half an hour to the island of Nusa Lembongan, which is a Manta hot spot. Just before my 27th Birthday we headed out to the aptly named, Manta Bay dive site. Having heard from people who had been diving that site in the days prior, that the Mantas were nowhere to be seen, so I had everything crossed that our dive would be different… Well, it must have worked a treat, because during the entire 45 minute dive, we had 14 or so Manta’s swimming all around us, through our bubbles, doing flips and turns just metres away. And members of the Aquatic Alliance, who had joined us on the dive, even snapped a few new rays to add to the worldwide database.
The worldwide database exists because Manta rays have been declared ‘vulnerable to extinction’ by the IUCN Shark Specialist Group. Anyone is invited to submit their Manta photographs via the Manta Trust website, where the team will determine if the Manta is already listed in the database, or in fact, an unlisted Manta. (Please read the ‘ID the Manta’ guide first)
The genus Manta contains two species of manta ray: oceanic Giant manta ray, Manta birostris, and the Reef manta ray, Manta alfredi, which is sometimes referred to as the Coastal manta. They are the largest rays in the world and are part of the elasmobranch subclass, as are all rays and sharks, meaning their skeleton is not made of bone like normal fish, but cartilage. Unfortunately cartilage leaves no trace in the fossil record, and so their existence was impossible to date until their teeth were eventually discovered, proving they have been swimming in the earth’s oceans for an estimated 5 million years.
Here’s a few more things you might not already know about Mantas:
- They can be up to 25 feet in length and weight as much as 5,000 pounds.
- Some types of Manta Rays engage in the process of migrating.
- They can lose their protective mucus membrane if they are touched by humans.
- The Manta Ray has the largest brain to body ratio of all sharks and rays on Earth.
- You will very rarely find any Manta Ray in captivity due to their size. They are currently only found in four aquariums in the world.
- The average life span for a Manta Ray is 30 years.
- They are very close relatives of the shark. Ironically, sharks as well as whales are their main predators. They are also closely related to the stingray but they don’t have a stinger.
- They are amazing when it comes to the acrobatics that they display.
- The Manta Ray is classified as a fish. It is one of the largest and it continues to be one that we know the least about.
- They don’t have a skeleton that is made from bone.
- The smallest species of Manta Ray is the Mobula Diabolis. It is only about 2 feet in length.
- There are myths that the Manta Ray will consume people but they are false. They are very gentle creatures that are able to get close to humans without harming them.
- The Manta Ray is only surpassed in size in the marine world by sharks and whales.
- While the Manta Ray has many rows of sharp teeth, they aren’t used for eating. Instead they have a filtering system.
- The Manta Ray doesn’t have a nose.
- The name Manta means blanket, and the fact that this creature looks like a blanket as it moves in the water is part of the namesake.
- The mouth of the Manta Ray is located on the top of the head instead of on the bottom.
- They are the only jawed vertebrates that also have limbs.
- The movement of the fins through the water is very similar to that of a bird flapping its wings.
- Many Manta Rays blend in well at the shoreline. They tend to get stepped on by people who don’t have a clue what is below their feet.
- They are extremely fast swimmers and also considered to be one of the most graceful as they move around. If you don’t look quickly though one can be gone before you realize it was there.
- Manta Rays are an endangered species and are listed by the IUCN
So what’s the problem?
Global manta and mobula ray populations are currently unknown. Even the leading scientists interviewed for this project were not prepared to offer estimates on global populations for any species. Likewise, many questions remain unanswered regarding their biology and behavior. What is known, however, is that these species are slow to mature (8-10 years+), are long-lived (40 years+), and reproduce very slowly. A manta ray will give birth to as few as a single pup every two to five years. By comparison, the Great White Shark, a highly vulnerable species protected under Appendix II of CITES, may produce more young in one litter than a manta ray will in her entire lifetime. Further underscoring the vulnerability of manta rays, scientists believe that specific regional populations may be genetically different from other populations.
These characteristics make manta and mobula rays extremely vulnerable to overfishing, regional depletion and local extirpation. While they are also taken as bycatch in certain fisheries, these rays are subject to significant directed fishing pressure throughout their range. Indonesia, Sri Lanka and India have the largest documented fisheries, with targeted fisheries also reported in Peru, Mexico, Thailand, China, Mozambique, Ghana, and other locations. Total annual documented global landings are ~ 3,400 mantas (M. birostris only) and ~94,000 mobulas (all species). Unreported and subsistence fisheries will mean true landings are likely much higher.
While local subsistence fisheries for meat have been carried out for centuries, in the past decade the growing markets for gill rakers have significantly increased fishing efforts. A mature Manta birostris (oceanic manta ray) can yield up to 7 kilos of dried gills that retail for as much as US$500 per kilo in the Chinese market. Established shark fin trade networks have exploited the opportunity to profit from gill rakers, especially as shark populations have declined.
How do we fix it?
Manta ray tourism could prove to be an effective solution. Diving or snorkeling with mantas and money spent on related industries (travel, hotels, restaurants, etc) is estimated to generate approximately $100 million per year worldwide, which is exponentially more than the estimated $11 million per year generated by slaughtering rays for their gill rakers and body parts. The same report calculated that a single manta ray could bring in an estimated $1,000,000 over its lifetime to tourism affiliated businesses, as opposed to the paltry $500 dead, in the fish market (often less). Hawaii estimates their mantas provide approximately $8 million in revenue per year in tourism related income, and in Indonesia it has been proven that an organized effort to protect and create a manta ray tourism industry could really boost their annual income if they were to utilize and manage this amazing natural resource in a proper manner.
Populations are currently stable, at best, around tourism sites or within marine reserves where manta rays are protected. Regionally, several nations and states have passed laws specifically prohibiting the landings of manta and mobula rays. The United Nations’ Convention of Migratory Species (CMS) recently listed the giant manta ray (M. birostris) as a species of international concern, but there are no binding international protections for any manta or mobula species, nor are they currently regulated by the Convention on International Trade in Endangered Species (CITES).
And most recently, in February Indonesia announced the world’s largest Manta Sanctury, encompassing a massive 6 million square kilometres of ocean, effectively enforcing full protection for Manta Rays! The Ministry of Marine Affairs and Fisheries, Pak Agus Dermawan signed the agreement in Jakarta which bans the fishing of manta rays in Indonesian waters. This comes after years of incremental steps forward, including a Manta & Shark Sanctuary in Raja Ampat and more recently, a reserve around the Komodo Islands.
If you’d like to see internation portection for Mantas you can sign the petition HERE
If you’d like to join a volunteer programme visit the Manta Trust volunteer page HERE