Hello Cyclone family, we’ve got a packed edition of behind-the-scenes of manta research for you!
This month we discover the manta secrets of northern Raa Atoll in the Maldives, and learn about how best to snorkel with mantas, following our recent study on the impact of tourists and manta interactions.
We kick off with a short video from Isabel Ender, who heads up our Global Mobulid Conservation Programme. She explains about the current threats to manta populations and how your support is helping reduce these threats by working with fishing communities around the world.
Our ‘Meet the Team’ feature comes from the Maldives this month. Audrey and Simon, our Research Officers for our Maldivian Manta Ray Project are exploring the northern atoll of Raa and discovering lots of new baby manta rays to add to our database.
As I write this there is much excitement as our team in the Maldives have just reached a historic 400 oceanic manta ray sightings . . . and there is hope that this season in the Maldives we may even pass 500!
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UNLOCKING THE SECRETS OF RAA ATOLL
Audrey Chartraud reports on her explorative mission in Raa atoll with Simon Hilbourne, both Research Officers for our Maldivian Manta Ray Project. Armed with their fins and cameras, these guys are already making some exciting discoveries after only two weeks… and taking some stunning photos as they go!
Earlier this year, Simon and I started a two month scoping project in the south west of Raa atoll. Raa atoll is located in the west of the Maldives just north of Baa atoll, home of the famous Hanifaru Bay. We already know a lot about the amazing manta ray population in Baa atoll thanks to the long running monitoring programme at our main project site located at Four Seasons Landaa Giravaaru. Daily surveys of the area during manta season from June to November have identified 2025 individuals from over 34,000 sightings!
The situation is different in Raa atoll. So far, we have only received manta sightings from citizen science and infrequent diving expeditions run in the area, accounting for a total of just 1100 sightings and 550 individuals identified. By having a Manta Trust project in the area, within the last few weeks we have already seen these numbers start to rise and we are hoping it will keep going that way. It is the first time a Manta Trust project has been based in Raa and our peak manta season here will run from December to April during the north east monsoon. During the off season, we will still be able to find manta rays on the east side of the atoll, we will just have to travel a little bit further away.
The scoping project has been very successful so far, and after only two weeks we have already identified 83 different mantas of which 24 are new to our database, including 12 pups! We have identified four main locations where mantas can be spotted and will hopefully discover more in the next few weeks as our adventure continues. We are still identifying new mantas every day we spend in the water which is very exciting!
Once the scoping project is complete, two research scientists from Manta Trust will take over starting from July/August 2019. The establishment of a Manta Trust project in this atoll will add greatly to our database as we will start to have more consistent data from this region. This project shows there is so much more to discover about manta ray population in the Maldives. In fact, being so close to Hanifaru Bay which is considered to have the greatest aggregation of manta rays in the world and has already been heavily monitored, and yet still identifying new individuals every day means there must be so much more out there! It just goes to show the importance of expanding our research project sites into new locations for unlocking the secrets of the Maldivian manta ray population.
PROTECTING THE MILLION DOLLAR MANTAS
Annie Murray, a Research Officer for the Manta Trust has been studying manta ray social behaviour as part of her PhD. Here she gives us some fascinating insight into her research of the impact of human interactions on manta behaviour.
The Maldives Archipelago has the world’s largest recorded population of reef manta rays, making it a hotspot for tourists to snorkel and scuba dive with these marine favourites, and the tourist industry is worth $8.1 million (worldwide manta ecotourism generates $140 million annually).
Manta ecotourism is a growing industry, with increasing numbers of tourists wanting to have an encounter with enigmatic manta rays.
As pressure on manta hotspots around the world grows, how can we ensure it remains sustainable, and avoids disturbing or altering the mantas’ natural behaviour?
This was the subject of a study carried out in the Maldives by Annie Murray from the Manta Trust and Eleanor Garrud, from York University.
What did the researchers look at?
During the busy manta months of July and August they spent two months collecting a large amount of data from key manta snorkel locations, observing and monitoring the human interactions as people snorkelled with manta rays.
The researchers used a specially designed research protocol to test the science behind these interactions. They established specific human behaviours, approaches and distance parameters to identify when mantas were disturbed or stopped feeding, during human-manta interactions at snorkel locations in Baa Atoll, Maldives.
How could snorkelling be harming mantas?
Manta rays are known for their docile and curious nature and in certain parts of the world aggregate in large numbers, sometimes exceeding 200 individuals in order to feed on ephemeral zooplankton blooms.
These thick concentrations of food can be rich and dense but also fleeting, therefore any disturbance to their feeding behaviour can drastically impact manta health. Many of the key manta snorkel locations in the Maldives are at these feeding sights, hence manta rays are being exposed to increasing human presence in the water during this vital activity.
So, what did the study find?
Of the total human-manta observations we made, passive interactions were the most common human behaviour recorded, making up 39% of all interactions while the most intrusive, chasing, luckily made up the least at just 5%. Our study highlighted the importance of allowing mantas to control the interaction and giving them space, which ultimately resulted in significantly less avoidance behaviour, thus making for a better experience. We found that when snorkellers approached within three metres, manta rays exhibited avoidance behaviour 31% of the time but this fell to just 3% for approaches between four to five metres. Accidental obstructions, diving too near/in front and chasing encounters were all significantly more likely to result in manta rays stopping their feeding than passive interactions, thus it is vital that snorkellers remain calm and still to avoid disrupting their natural behaviour.
What’s the best way to snorkel with manta rays?
The study produced these recommendations with for anyone in the water with manta rays;
Maintain a distance of three metres or more when approaching,
Remain passive throughout interactions avoiding splashing, touching or chasing animals,
If approaching animals, always approach from the side, within the manta ray’s field of vision,
Avoid diving directly in front of the animals
Only experienced snorkellers should attempt to free-dive near manta rays.
The study is now looking at scuba divers interactions with manta rays at cleaning stations throughout the Maldives. One this research is completed they hope to set parameters for nationwide government legislation in countries where manta ray tourism activities exist.
The ultimate aim is for manta ray tourism to become a safe and sustainable alternative to fishing, without altering the manta rays natural behaviour, and one which will produce lasting financial gains for the local economy and tourism trade.