Hooked on Manta Rays
No one forgets their first manta – this is a phrase that I’ve heard uttered by many of my scuba diving and marine scientist friends, and I couldn’t agree more. I certainly won’t forget mine! The interaction occurred last summer near the beginning of my six months spent with Barefoot Conservation in Raja Ampat, Indonesia, an organization providing volunteer expeditions to assist in reef health and manta ray surveying. The summer is the region’s manta low season and, at the time, we were performing only one manta survey dive per week. One morning we had just begun our survey dive at Manta Sandy, a cleaning station only minutes from our base camp. Mantas visit sections of reef known as cleaning stations regularly for their “bathtime”, where a variety of different fish will eat any parasites, bacteria, and dead skin from the body and gills of the manta (and sometimes the ears of divers). The visibility on the cleaning station that day was not the region’s typical 20 meters (about 65 feet) but was, instead, a bit murky. As I looked around me, I suddenly saw a big majestic creature swim out of the blue towards us. My first ever manta was as beautiful as I had imagined, and even bigger than I thought!
As I became increasingly spoiled by Raja Ampat’s amazing diving, I began to lose my manta excitement, which I attribute to spending a few too many 45 minute manta survey dives sitting without seeing anything. However, as the manta season picked up, I was able to squeeze back on to a few extra manta survey dives and I began to fall back in love with these amazing animals. During the manta high season, a slow day changed from 0 mantas seen to about recording about five different individuals per survey dive. Returning from this type of “slow” manta survey dive, our group spotted a group of mantas swimming near the surface of the water. After quickly donning our snorkels and slipping into the water as quietly as possible (with only a couple of big splashes), we were surrounded by mantas. There were individuals below us, beside us, and, seemingly, barrel rolling straight into us! These mantas were all there feeding on small plankton suspended in the water column. Mantas feed using RAM feeding, swimming forward with their mouth open to eat suspended, non-swimming plankton. Barrel rolling is a type of feeding behavior used by mantas to continue feeding on food that is focused in one area.
After this incredible snorkel, my love for the beautiful manta was back full-force! My next manta dive was a trip to a site new to me, Manta Ridge, and things just kept getting better. As we descended over the ridge onto the dive site, we hooked into bits of dead reef and rock. The Manta Ridge dive site is considered an advanced site and is known for its strong currents, which are believed to attract the mantas to the site. As we floated around in the current, staying on the dive site thanks to our reef hooks, the graceful mantas began to appear and just kept arriving. The mantas were hovering right over our heads and on both sides of us, allowing our researchers from the Marine Megafauna Foundation to get incredible identification photos, and even allowing me to get a tap on the head from a manta’s fin! I was in awe watching these incredibly graceful swimmers and couldn’t help but laugh when I would glimpse my fellow divers being whipped around by the current and small whirlpools below the manats, who thrived on feeding in these currents and who were just hovering in place.
After my manta ridge dive, my love for the amazing mantas continued to grow. On my last weekend in Raja Ampat, I was able to join our manta team on a dive at Blue Magic, a site known to be a giant manta (Manta birostris) cleaning station. Up until this dive, I had been seeing reef mantas (Manta alfredi) near our project base, so I was excited to head out to a site where we might see the giant manta. There are currently two described species of manta ray – the reef manta (M. alredi) and the giant manta (M. birostris). As the name suggests, giant mantas grow larger than reef mantas, with the giant manta reaching sizes up to 7 meters (about 23 feet) disk width and reef mantas reaching disk widths up to 5 meters (about 16 feet). There are many other morphologic traits that are used to differentiate between the two species of manta, with differences in coloration serving as easy tools for divers to differentiate between the two species. The list of morphological differences between M. birostris and M. alfredi were formalized in 2009, when prominent manta researcher Andrea Marshall and her team formally described reef mantas, introducing the two different species of manta. You can find more information about manta rays, including species differentiation, and their relatives here. There is now strong evidence that a third distinct species of manta exists, living only in the Atlantic and Caribbean. Despite being mentioned in Dr. Marshall’s 2009 description of M. birostris and M. alfredi, this possible new species has not yet been formally defined. Dr. Marshall and her team are currently working towards defining this new species.
As we begun our giant manta survey dive, we kept our eyes open for possible giant manta sightings while taking in the beauty of large schools of fish, beautiful coral formations, and several wobbegong sharks living on this underwater pinnacle. After about thirty minutes enjoying this amazing dive site, we spotted a large manta swimming out of the blue towards the pinnacle. Everyone in our group carrying cameras quickly pulled them out as we waited for the manta to approach. True to its name, the giant manta looked huge and was absolutely stunning! Our team was able to get quite a few identification photos of the individual before we had to begin our safety stop and leave our beautiful manta behind.
There are not many places in the world where giant and reef mantas are sympatric, meaning populations of both species live in the same area. Parts of Hawaii, Indonesia, Mozambique, and French Polynesia house sympatric manta populations, making these areas big treats for manta loving divers and snorkelers. However, within these areas, the two species tend not to come into contact with one another due to smaller scale habitat use and seasonal migration patterns, among other things. It is, therefore, unlikely that divers will encounter both species of manta on one dive site, explaining why my research dives to encounter each species of manta had to be on different sites.
Most people who have spent time in the water with one or many beautiful mantas cannot help but want to make sure that these gentle giants are afforded protection. This supports the conservation idea that one of the best ways to encourage conservation and protection of any species, but especially those awe-inspiring, big, beautiful species, termed charismatic megafauna, is to see these animals first-hand. Therefore, many conservationists work to encourage responsible ecotourism as a way to engage the public in conservation. I include the word responsible in my description of ecotourism to underscore the importance that all swimmers, snorkelers, and divers in the water with mantas do not stress the animals. Mantas are extremely intelligent and curious animals, but irresponsible actions, including chasing or harassing individuals and damaging their habitat, will negatively impact the mantas and their behavior. When interacting with mantas, it is important to remain still and calm, keep off their cleaning stations, and allow the manta to dictate the interaction. I can attest to the inquisitive nature of mantas and, if you remain still it is very likely that a curious manta will approach you and swim right over you! Responsible ecotourism is also a fantastic way to support local incomes and increase the value of living mantas, creating alternative livelihoods for people who may resort to fishing these animals for a one-time payment at market.
Manta rays are being threatened by the gill raker trade, which is creating the large market for fished mantas and is causing overfishing of both species of manta. The gill rakers help to filter plankton out of the water for the mantas to eat, and they are now sought for use in Chinese medicine. The capture of these beautiful animals purely for a tiny portion of their bodies is devastating manta population numbers and is hugely threatening to their survival. More protection, and enforcement of current legislation, is needed to protect these wonderful animals, and much more research is needed to fully understand mantas. Anyone can help support manta conservation by supporting national and international legislation to protect mantas and their ocean home, supporting manta research through financial contributions to a variety of research focused organizations, or, quite simply, participating in a dive or snorkel trip to show tour operators the high economic value of living mantas.
If you wish to go a step further and play an active role in manta research, there are several expeditions that you can join around the world. Barefoot Conservation, where I spent my time, offers year-round volunteer expeditions that allow you to work on reef conservation, manta ray research and conservation, and community outreach projects. You can also join Andrea Marshall, the queen of mantas, and other Marine Megafuana Foundation experts on a Ray of Hope Expedition, where you can learn about mantas and other megafauna species while also contributing to research efforts. In addition, the Manta Trust also runs similar expeditions to important manta research sites around the world. Another way to contribute to manta research is through citizen science. The manta matcher site allows anyone to upload photos that they have taken during manta encounters, contributing directly to studies looking to enhance our understanding of manta migration patterns, population size and composition, habitat usage, and changes in manta populations.
It is my hope that by promoting responsible manta ecotourism and increasing international conservation efforts, more and more people will be able to have their own first manta encounter story now and in the future.