MANTA RAYS : Majestic and Mysterious

Manta Rays are among the most majestic gentle giants in tropical and sub tropical oceans of the world.  Seeing them swim under water is a magical sight to behold; with their mouths wide open, manta rays silently move through the water in a slow, effortless, gliding motion, feeding on the smallest of living creatures, plankton, that drift in the ocean currents.   Like many species of sharks, mantas are in constant motion to keep water flowing over their gills to breathe.  Additionally, mantas are cartilaginous fish meaning their skeleton is made of cartilage like our ears and noses.

There are two species of Manta Rays: the Reef Manta (Mobula alfredi) and the Oceanic Manta (Mobula birostris).  No matter the species of manta, With their wings outstretched they dwarf all but large sharks or whales.  The reef mantas wings span up to 5 meters while the oceanic mantas wings span up to 7 meters and can weigh up to 2 tons.  Manta Rays have the largest brain to body ratio of all living fish and are known to display high levels of intelligence, have long-term memory, and are able to map their environment using sights and smells.  The markings on their underside are their unique ‘fingerprint’.  Much like the marking on the underside of a humpbacks tail, the star-like pattern of whale sharks, and the whisker spots of lions, there are no two exactly alike and these creatures can be identified by their markings that make them unique.

As seen in this photo above there is a mutualism, or mutually beneficial relationship, between mantas and various small hitchhiker fish like remoras.  The Remora clings onto the Manta Ray for protection, transportation and scraps from the Manta Rays meals. The Remora benefits the Manta Ray by cleaning it’s skin of bacteria and parasites keeping Mantas healthy.  Manta Rays can also be found at ‘Cleaning Stations’ (or healthy coral patches) sometimes circling close by for up to an hour before moving in for a cleaning and then staying on for hours getting cleaned.  In this case the mantas have a symbiotic relationship with cleaner fish (like the cleaner wrasse fish and the scarlet cleaner shrimp). These small fish and crustaceans swim around the larger animals and inside their mouths to eat the parasites, bacteria, and dead skin cells from their bodies.  One animal is getting fed while the other is getting cleaned.  It’s a win-win!  Manta Rays will often return to cleaning stations they ‘know’.

Manta rays live up to 50 years.  The female manta becomes sexually mature a bit later than the male: round 8-10 years of age.  Manta rays are ovoviviparous meaning that after fertilization the offspring grows inside an egg (like a bird…but WAIT…there’s more)…which the female manta carries inside of her during the pregnancy and give birth to a live fully independent manta ray (live birth like a mammal?!).  Mantas give birth to 1-2 manta every 2-5 years.  Many details are still a mystery as no one has ever documented seeing a live birth in the wild.

Perhaps because of their size, their grace, their omnipresence in the oceans Manta Rays, and many other characteristics, manta rays have found their way into the art and mythology of many cultures around the world.  In Polynesian mythology, for instance, the manta ray is believed to be the guardian of the ocean and a symbol of knowledge and wisdom.  In ancient Greek mythology, they were believed to be messengers of the sea god, Poseidon.   In ancient Hindu mythology, manta rays are believed to be the manifestation of Lord Vishnu, the creator of the universe. In Japan, manta rays are often associated with the god of the sea, believed to protect sailors and fishermen from danger and provide them good fortune.  Interestingly, they are universally seen as protectors and not aggressors, creators not destroyers.

Sadly, as much as manta rays are widely admired to revered their existence is threatened in various ways.  Being pelagic, they cross ‘borders’ constantly and live in a warming ocean that is thereby struggling with habitat loss and teaming with industrialized fishing techniques that do not take care to avoid them (mantas are often ‘bycatch’ and can die due to suffocation as a result of entanglement.).  In some places mantas are specifically sought out for food and bait (for instance in the Sea of Cortez, Mexico) and in the western south Pacific mantas are harvested for their gill plates that are used in Asian Medicine.   It is worth noting that in Indonesia, Peru, and the Philippines there now national laws in place to protect manta rays.

Still, in order to protect animals, we need to understand them.  Efforts are being made to understand manta distribution, mating, and ecology better to help them.  However, Scientific efforts to understand Mantas formally began rather recently around 2008.

According to Mantatrust.org  :

Manta rays often undertake seasonal migrations, travelling tens, hundreds, and sometimes thousands of kilometers. This means that their habitat can encompass large areas, sometimes crossing national boundaries, where conservation management is often more challenging. Therefore, to effectively protect these animals, we must first understand what habitats they are using, when they are there, and what they are doing within it. 

….It is often a sad fact of human nature that the more endangered a wild animal becomes, the greater our desire to possess or consume it. Diminishing stocks drive a lucrative trade (often illegal) to hunt down, trade in, and consume the dwindling populations of these endangered species.

Interestingly, again there is still so much mystery around mantas that citizen scientists are helping with these efforts.  People can communicate directly with the scientists at Manta Trust to help supply information (pictures) to create a ‘mantabase’ about specific manta individuals to share where they are and begin to help map their health, habitats, and seasonal routes.

If you are a mariner, look out for this incredible species of fish.  Maybe you can appreciate their majesty while unlocking some of their mystery.