Manta rays are on the top of most divers’ bucket lists. They were certainly on mine for a long while before I had the privilege of being graced by a manta’s presence. I’ve been on several tours where the chance of seeing mantas was highly likely, like in Bali, Australia, and Mexico, but it wasn’t until I was out on the water every day in South Africa that I finally got to experience my first manta.
There are two subspecies of manta ray, discovered only in 2008 (they were previously thought to be the same species), and I had the pleasure of swimming with both the reef manta and the giant oceanic manta in Sodwana Bay, South Africa. The reef manta tends to stick to the Indo-Pacific coast and is much smaller, with a wingspan of only 11 feet (just over 3 meters), while the giant oceanic manta has a wingspan of 29 feet (almost 9 meters), and is found far from land in all oceans. It was an honor to experience both subspecies.
Just a few months later, on Mermaid Week Maldives with Mermaid Kat, my manta experiences were enhanced even further when I got to dive with several mantas at a time! We even had a manta visit our boat at night and several mermaids got in for a night swim with the gentle giant.
Oceanic mantas prefer to be alone or in small groups but congregate to feed. Both subspecies are filter feeders, meaning they swim with their mouth open, drawing in water filled with yummy zooplankton and krill. The food is then separated from the water with the help of their gill plates, which are rows of tiny rakes that line the manta’s mouth. Manta rays are known for their unique ways of feeding - and I was lucky enough to see both methods first hand!
The first fun way of feeding was observed during that night the manta came to swim with us behind the boat. The manta was continuously doing somersaults to stay in a single spot that was packed with krill and zooplankton. This gave us mermaids and our photographers plenty of time to get pictures with the manta as he kept spinning off the back of the boat for hours eating away. Being sure to give him his space of about 3 meters, we tossed and turned in the ocean with this magnificent creature until we’d had our fill.
The other common way mantas like to feed was spotted on our daily dives. This method is called chain feeding, and occurs when manta rays follow each other in a circle. This creates a cyclone effect which traps food in the spiral, allowing them to filter feed with their mouths open in a rich environment.
Manta rays also like to visit cleaning stations regularly. They even remember which one they like and return to the same cleaning station over and over! At the cleaning station, they stay still while cleaner fish remove parasites and dead skin from their bodies. Manta rays are highly intelligent, as proven by their memory to return to the same cleaning station. In fact, they have the largest brain-to-size ratio of any cold-blooded fish! They use smell and visual cues to create mental maps of their environment, which demonstrates their highly developed long term memory. There have also been studies that illustrate that manta rays can recognize themselves in mirrors! This shows a high cognitive function, similar to that of elephants, monkeys, and dolphins!
Manta rays are descriptively named, as manta means blanket or cloak in Spanish, which is how one might describe a manta’s large, diamond-shaped, flat body. They’re also called a devil ray or devil fish, which arises from the two fins that come out of the front of their head, looking like horns. Mantas have triangular pectoral fins as well.
Manta rays give birth to 1 or 2 live pups every couple of years. Female mantas reach sexual maturity around 8-10 years old and pregnancies last 12-13 months. Once born, the pups can survive immediately without any parental care and they look just like a smaller version of adult mantas. Manta rays can live up to 50 years.
Due to their long lives and slow reproduction cycles, manta rays are considered highly threatened. The International Union for Conservation of Nature (IUCN) Red List of Threatened Species lists Manta Rays as Vulnerable, which means it “meets one of the 5 red list criteria and thus considered to be at high risk of unnatural (human-caused) extinction without further human intervention”. The greatest threat to manta rays is overfishing. It’s very hard for manta rays to bounce back when they’re fished, but they continue to be fished for their meat and gill plates. Thousands are killed each year for the gill plate trade, which brings in about $30 million per year. Manta rays are considered a delicacy by some and although there is no proof of their medicinal benefits, the Chinese use them for medicines ranging from chickenpox cures to increasing blood circulation.
There is some relief! In 2011, manta rays were added to the Convention on Migratory Species which is an international treaty that protects migrating wild animals from being fished in international waters. In 2014, Indonesia, which was the world’s largest manta ray fishery, created a ban on fishing and trading manta rays, as they found out they could make more money by using live, wild mantas for tourism instead. A manta ray was only worth $500 dead, but a single ray in a tourist hotspot can generate over $1 million in revenue. Ecuador, Peru, Mexico, the Philippines, and New Zealand all have their own fishing bans in place as well.
You can help the manta rays by writing to government officials in favor of manta ray fishing bans, promoting the aspect of tourism instead. Don’t purchase anything made of manta ray, especially gill plates. Be an eco-tourist and make sure you are using a reputable company, and if you do get lucky enough to swim with a manta make sure you respect it! Don’t chase it; let it come to you, and make sure you keep a healthy distance; don’t touch! Have fun enjoying and supporting the ocean’s angelic “devil fish”.