Mola Mola: ‘Bullet-Proof’ Wonder of the Deep

By Sophia Read

For The Bali Times

SEMINYAK ~ At this time of year, dive centers in Bali are buzzing with talk about the Mola Mola.

“Did you see Mola?”  is the question fired at still-dripping divers as they disembark from the boat, or descend from their transports. You can easily tell the divers who did from the ecstatic and slightly bemused grins that cover their faces.

So what are these Mola Mola?

Despite the name, the Oceanic Sunfish (Mola Mola) bears little relation to the sunbirds common to Bali. The name Mola Mola comes from the Latin “mola,” meaning millstone, and could not really be more apt. Around the world they bear different local names – the Italian, Spanish and Dutch names both mean Moon fish (referring to their shape), not Sunfish. The Germans refer to them as Schwimmender Kopf – or swimming head – and the Taiwanese have perhaps the best name of all: the “toppled car fish.”

All these names suit the Mola Mola well. They are essentially gigantic, flattened spheres, as tall as they are long. The Mola Mola has no true tail, giving it a unique shape, and leading to the name “Head fish.”

They are gigantic – a specimen has been recorded at 3.1 meters in height (it ran into a ship carrying cement off Australia – the collision caused the ship to loose almost a third of its speed. When the Mola Mola was weighed, it was recorded at 1,400 kilograms). The average size of the Mola Mola is estimated to be approximately 1.8 meters from the snout to the end, and the average fish weighs 1 ton (only half the ship-stopping specimen).

Bali is a great place for an encounter with these weird and wonderful creatures. Very little is known about why they appear when they do, but we surmise that the currents bring them up to recreational diving depths. This happens from August to October every year, but this year, they are here already.

They really aren’t particularly good swimmers – though, don’t try and tell that to an underwater photographer who has just focused on the perfect shot, only to see the fish rocket down into the depths after being poked by a particularly idiotic diver. The lack of a tail means they have to propel themselves along using both the dorsal and anal fins, giving them an easily identifiable “sculling” motion, completely unlike other fish. They seem to steer using their gills – squirting water out of one side of their bodies or the other.

They have been seen deeper than 500 meters, and there is one theory that the “sun bathing” behavior that gave them their name may be a way of reheating after a long time in the cold depths of the ocean.

More widespread is the theory that they ascend to recreational diving depths to take advantage of the multitude of other fish that are delighted to clean them – they even seem to deliberately attract seabirds to help with this task, as they lie on their sides at the surface. You can understand this behavior – more than 40 different types of parasites are known to infest them.

Oceanic Sunfish are totally harmless to humans – unless you are in a boat that collides with one – and diving with them is an awe-inspiring but utterly benign experience. They have very few natural predators, due to their massive size, and their incredibly thick outer layer: they have more than 5 centimeters of solid gristle under the skin. The skin itself is incredibly rough – in the encounter with the cement ship, the Mola Mola’s skin scraped the paint down to the bare metal on the hull. If you consider that this is normally the job of a large team of skilled men equipped with industrial solvents and acetylene paint strippers, you can see why harpooners considered them “bullet proof.”

They eat a varied diet, including jellyfish, squid, sponges, crustaceans and small fish. Their jaws form a beak, and they also have teeth in their throat, to help grind their food as it makes its way to the stomach. It is mainly from analysis of stomach contents that we are able to deduce that they spend the majority of their lives at depths that the recreational diver will never reach. We know very little about their mating habits, though a female can produce up to 300 million eggs at one time.

Mola Mola young look like tiny, tiny pufferfish (less than 0.5 of a centimeter long). They do, however, seem to grow at an incredible rate – a juvenile caught by the Monterey Bay Aquarium in the United States had to be airlifted to freedom after it outgrew its tank; its weight had increased more than 14 times in less than two years.

They are considered a delicacy in several countries – mainly Japan and Taiwan, and are frequently caught by accident by fishermen drift-netting. Marine rubbish is also a major cause of fatalities – floating plastic bags closely resemble the jellyfish that form the mainstay of their diet. Finning (the removal of the vital dorsal fins) is observed by sea-lions in the wild, and echoed by fishermen who regard these gigantic flattened orbs as bait thieves.

Mola Mola are fish of very little brain. The brain is smaller than the spinal cord (normally shorter than an inch). They are surprisingly easy to train (yes, fish can be trained), and have been taught to feed from the end of a pole, and even, in some cases, from human hands – but that has only been done in an aquarium. The Mola Mola off Bali in no way benefit from human contact. They do not want to be touched, poked or squirted with air to demonstrate how fast they can move when annoyed or disturbed.

The sites around Nusa Penida are not for beginners; they are frequently subject to unpredictable currents and strong surge. Mola Mola are often sighted considerably deeper than the Open Water limit of 18 meters. Open Water divers who want to include this incredible experience in their Bali holiday should consider the PADI Advanced Open Water Course. This involves no classroom work – only 5 dives, including a deep dive. You might even spot some Mola Mola.

The writer is sales manager for AquaMarine Diving – Bali.

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