Komodo Manta Sites: What the Rays Are Doing at Each One

Four sites, four different jobs

Many people imagine a manta site as a place where mantas simply are. In Komodo National Park, research tells a more interesting story. Using a long-term photo library built by researchers, trained dive staff and citizen scientists, a team identified 1,085 individual reef manta rays from photographs taken between 2013 and 2018, and looked closely at four sites visited by tour operators. The study, led by Elitza Germanov and published in PeerJ in 2022, is the main source for this article.

The sites are physically very different. Cauldron, in the north, is a shallow channel of less than 25 m between two islands, with complex structure and strong tidal currents. Karang Makassar, in the centre of the park, is a gently sloping rubble field less than 18 m deep that runs about 1.5 km, with patchy reef and coral heads where mantas are cleaned. Mawan, about 5 km to the east, has a shallow cleaning station at 5 m on a sandy slope. Manta Alley, in the south-west, lies about 35.5 km from Karang Makassar, in a bay of rocky islands with channels exposed to surge and strong currents, and sloping reefs to about 35 m with several cleaning stations.

What the mantas are actually doing

Across 2,306 behaviour records from the three main sites, plus a smaller set from Cauldron, the researchers found a clear link between site and behaviour. Mawan had the highest share of cleaning, 74%. Karang Makassar followed with 53% and Manta Alley with 39%, while Cauldron had just 6%. Cruising dominated at Cauldron (74%) and was common at Manta Alley (45%), both places where mantas often swim into the current through narrow channels. Foraging was rare at Mawan (1%) and most common at Cauldron (20%). The largest feeding event, up to 30 individual mantas identified in one day, was recorded at Karang Makassar during the north-west monsoon.

Courtship was seen at every core site except Cauldron, and it happened throughout the year. The authors suggest that cleaning stations may also act as lekking sites, places where courtship and competition for mates take place. A cleaning station, then, is not only a place to remove parasites. It may be one of the social centres of manta life. We explain the cleaning itself in what a manta cleaning station is.

Who uses which site

The three main sites, Karang Makassar, Mawan and Manta Alley, had similar profiles dominated by mature mantas, with an equal ratio of males to females overall. Cauldron was different. It had proportionally more immature males, fewer visibly mature females, and more feeding. The researchers note that the limited data from Cauldron point towards all three accepted criteria for a nursery area, but they could not confirm it without accurate size measurements and tracking.

Mantas are also loyal to particular places. Karang Makassar and Mawan are only about 5 km apart, yet individuals showed distinct site affinities. Most mantas, 72%, were seen more than once at the core sites, 56% across several years, and one individual was re-sighted 13.4 years after it was first photographed. Females moved between sites more than males, and 11 Komodo mantas were also photographed in the Nusa Penida Marine Protected Area near Bali.

Why the water decides

The different roles make sense once you look at the water. Tidal currents through the park reach up to about 15 km/h in the Lintah Strait, carrying Indian Ocean water north on the rising tide and Pacific water south on the falling tide. Upwelling to the south is strongest from June to October, during the south-east monsoon.

Manta Alley faces the Indian Ocean and deep basins, so it is enriched directly by that upwelling, and manta sightings there rise in the south-east monsoon. The central sites are sheltered by the big islands, so tides are probably the main way food reaches them, and visits increase on spring tides around the full and new moon. Cauldron, a channel that concentrates current and possibly plankton, appears to support feeding in the south-east monsoon, when the north is usually less productive. Each site is a small machine of tide, depth and shape.

Why Komodo's mantas need these sites to stay calm

Reef manta rays, Mobula alfredi, are listed as Vulnerable, and they grow and reproduce slowly. In Komodo, protection came step by step: manta fishing was banned in and around the national park in 2013, a year before Indonesia protected manta rays nationwide in 2014. The 2022 study is, in a way, a picture of what that protection made possible, with some of the largest reef manta aggregations known.

The same researchers were also clear about the next pressure: tourism. Their suggestions were practical, limiting the number of tour boats allowed at an aggregation site at one time, and making codes of conduct for diving and snorkelling with mantas mandatory. If cleaning stations are also places for courtship, and if one channel may matter most to young rays, then crowding is not only unpleasant for divers. It can interrupt the very behaviour that keeps a population healthy.

This is the ethical layer of a manta dive in Komodo: the animals are protected from fishing here, but not yet from us. Choosing a quieter time, a smaller group and an operator who will leave a crowded site is a real contribution, not a gesture. Wildlife encounters are unpredictable. Diving and snorkelling with manta rays should always follow local regulations and experienced professional guidance.

How to experience Komodo's manta sites respectfully

Once you know what a site is for, good behaviour becomes intuitive. At cleaning sites such as Mawan and Karang Makassar, the Manta Trust code of conduct asks divers to stay at the side of the cleaning station, not in it, to stay low without damaging the reef, and never to block a manta swimming overhead. Everywhere, it asks you to keep at least 3 m away, let the manta come to you, approach only from the side, never chase and never touch. At feeding or cruising sites such as Cauldron, that means not swimming into a manta's path while it feeds into the current.

The Komodo National Park protocol forbids touching animals or getting too close to them, dropping anchor in manta habitat or along manta routes, and driving boats at high speed near dive sites. A good operator chooses each site by tide and by your experience, briefs these rules clearly, and will change plans when a site is too busy. Strong sun and long surface intervals are part of Komodo days, so a long-sleeved rash guard is useful on the boat and in the water, and a roll-top dry bag keeps a phone and a warm layer dry on a fast boat transfer. If you snorkel at a manta site, stay on the surface and let the rays pass below you.

For a wider view of the park, see how rising popularity is putting pressure on Komodo's mantas.

To see how Komodo fits into Indonesia's wider ocean story, explore our Indonesia Ocean Atlas and the reef manta ray page. If this made you curious about meeting mantas this way yourself, you can explore our retreats.

Questions people ask

Wildlife encounters are never guaranteed and never forced. Ocean Calling works only with vetted, ethical local operators, and every animal is free to approach, or not, entirely on its own terms.