Ocean News

Saving mantas in the Maldives

8th December 2010

The Maldives are home to some of the biggest manta ray feeding aggregations in the world. The sight of dozens of these majestic animals gliding underwater draws a rapidly growing number of tourists every year. Thanks in part to project leader Guy Stevens’ work, one major manta feeding site has been proclaimed a marine reserve – a necessary first step to ensure these unique animals continue to thrive. We chatted to Guy recently about his work.

There are plenty of fish in the sea – why mantas?

The first time I saw a manta ray underwater, I was captivated by these amazing animals and I knew I wanted find out as much about them as I could. As a result, I created the Maldivian Manta Ray Project and now devote my time to researching and learning more about the Maldives resident population of manta rays.

How did you end up working with manta rays in the Maldives?

After graduating in Marine Biology from the University of Plymouth, UK, I moved to the Republic of Maldives to work as a marine biologist onboard the Four Seasons Explorer – a luxury liveaboard dive boat. As part of my job, I got to see manta rays on a regular basis while leading dive and snorkel excursions. That developed into a desire to learn as much about these graceful and inquisitive creatures as I could.

What is the impact of increasing numbers of tourists visiting the Maldives to dive with mantas? Are you seeing negative effects on manta populations because of this yet?

The levels of tourism at Hanifaru in 2010 were way above the regulations set by the government.

The more people who visit the Maldives in search of an encounter with manta rays the better; tourism really is important for the long term survival of these animals in the Maldives and elsewhere around the world. However, tourism needs to be managed so that it is truly sustainable. As specific sites, such as Hanifaru, become overwhelmed with tourists there is a growing need for effective management to ensure that this site does not become degraded.

It is very difficult to quantify the impacts of tourism on the animals themselves, however, the manta rays appear to be very tolerant of humans while they are feeding, which is the primary reason for the manta rays to visit Hanifaru Bay. Therefore, I believe that it is possible for everyone to benefit from Hanifaru, however, there are always limits to the tolerance of wild animals to disturbance and it’s this balance which we need to find for Hanifaru. Certainly the levels of tourism at Hanifaru in 2010 were way above the regulations set by the government when Hanifaru was declared an MPA in 2009.

Thanks in part to your work, Hanifaru Bay was proclaimed a marine reserve last year. Is the Maldivian government recognizing the need for sustainable management of marine tourism?

Yes, very much so, the Maldivian government is committed to ensuring Hanifaru is effectively managed and sees the economic sense in doing so. Unfortunately however, the wheels of bureaucracy and policy making turn much lower than is needed on the ground at the root of the problem, but this is the same wherever you go in the world.

Why are there so many mantas in the Maldives?

Because the Maldives is the perfect place for these reef mantas; there is plenty of food all year round, there are few natural predators, and most importantly in today’s world of human exploitation, there has never been a significant or commercial fisheries for manta rays in the Maldives.

What is the biggest threat mantas face today?

Fisheries to supply Chinese medicines! Manta ray gill rakers are fast becoming a highly sought after product in the Asian medicinal trade. The rakers are marketed as a cure for various ailments, including respiratory illnesses and circulatory problems; mantas filter the water for food vis-a-vis mantas gill rakers will filter your blood as well!

Drift nets and long lines entangle and kill mantas, mainly as a by-catch of the intended target fisheries. In Sri Lanka, the Philippines, Mexico and Indonesia manta fisheries have, or are in the process of decimating local populations, causing fishermen to venture further afield in search of new stocks to supply the growing demand for manta gill rackers in the Asian medicinal markets.

What are some of the most interesting manta behaviours you’ve witnessed?

When diving amongst a mass feeding aggregation of about 100 manta rays, I noticed an individual that was trailing a mass of fishing line. Before I could act in any way, the manta peeled away from the other feeding mantas in the water column and swam over to me, circling within inches of my head. It was a three metre female and as she moved closer I could see her injuries were severe. The line was completely wrapped around her body several times, slicing a wound about 30cm directly through her upper and lower jaw backwards into her head. The more she tried to open her mouth to breath and feed, the more the line dug into her flesh.

My dive buddy had already surfaced; I was at 15 metres, I had almost run out of air and my dive knife was on the research boat anchored 100 metres away. What should I do? I decided to get my knife! I exchanged my empty tank for the only other one which had any air left, still only about a quarter full, and to make matters worse it was beginning to get dark. It took me 15 minutes to get back down to the feeding mantas and I was worried that I had missed my chance to help. But as soon as I descended the injured manta again approached and began to circle me. I swam closer and began to cut at the line wrapped around her body; it did not take much to remove it all, especially as she remained calm throughout. With all the line removed the manta continued to circle, but I had to leave. I was almost out of air and it was nearly dark, so I quickly took some photos of her injuries and an ID shot so I could recognise her again if she survived.

This encounter is one I will never forget, the connection and sense of achievement was amazing and extremely rewarding for me. I just hope the manta is able to recover. And, in fact I think she will, because on several occasions throughout the following months I was able to again dive with her and see her injuries start to heal. These encounters were even more intriguing for me because she again left the feeding group and came to circle above and around me. She did this for several minutes before returning to feed and I was the only diver she approached despite the presence of several other people. I don’t really know what to make of this behaviour, as a scientist I try to rationalize and explain it logically; maybe through association with divers at cleaning stations the mantas think we are able to act as a kind of giant cleaner fish, removing fishing line and later by helping to further clean the wound. But I can’t help but think it’s more than that, I think she recognized me and was curious to learn and interact more with this strange person who had helped to set her free.

What advice would you give to an aspiring marine biologist?

Don’t sit around and wait for an opportunity to present itself; if you care about the marine environment, if it fascinates you and you want to learn more, then go out and make your dreams a reality because they seldom get offered to you on a plate.