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In Search of the Giant Mola A unique tagging project off the shores of Bali

The rarely seen, tropical mola-mola or ocean sunfish is one of those Holy Grail type of creatures that many divers and marine scientists would like to see but few have the opportunity. They have a round little mouth, set back eyes, huge anal and dorsal fins and virtually no tail. The can be 14 feet in height from fin to fin. The largest of the pufferfish family, these fish can weigh over two tons and are, without a doubt, one of the oddest looking creatures in the sea. And they play host to more than 40 genera of parasites on their thick skin. In Bali, Indonesia, in September of 2004, these fish were also sought ought by one of the most knowledgeable marine biologists on the planet. The goal: to place satellite tags on the unique giants to see just where they go and what they do.

Just across the Bali Straits off Bali's east coast lie the islands of Lembongan, Ceningan and Nusa Penida. Deep gorges and coral filled bays separate these islands and provide an area for cold water upwellings to bring nutrients to a vast variety of marine life. For some reason yet to be fully discovered, these sunfish come close to the coral reefs of these islands a few short months out of the year.  Following the cold upwellings, which can range anywhere from 17 to 21C, the sunfish emerge and head to cleaning stations. Tierney Thys, a National Geographic Emerging Explorer and internationally known marine biologist, was deploying satellite tags on the sunfish for the first time in a deep water environment like this. She is the world's expert on these highly unusual creatures.  Using Bali Hai Diving Adventures, a Bali based diving company headed by Michael Cortenbach thathas specialized in this set of islands for a decade, she

accompanied divemasters to the handful of sites that molas seem to like to frequent. Now tagging these creatures is new and is bringing some fascinating data to light about how the fish live. In temperate waters, they are seen seasonally around southern New Zealand, Southern California, the Cape Town area of South Africa and even the British Isles. They hang at the surface under kelp beds and are somewhat easily tagged by biologists using snorkel. The tags come loose by themselves after six months and then send back the data via satellite. Temperate molas come close to the surface at night, possibly to sleep or feed on rising food populations, and it was found but make a series of deep dives by day, probably to feast on jellyfish, one of their favorite repasts. But they also eat shrimp and squid.

Story and Photos by                Tim Rock

But the tropical kind of sunfish who make the shores of Nusa Penida a stomping ground are rarely found at surface. And when they are close to the reefs, it is only a couple months of the year. So, for the first time, it is hoped this work will shed some light on their movements. They successfully deployed tags at depths ranging from 75 to 150 feet down. Using a system designed by Brett Hobson, her ocean engineer husband, she employed  a pneumatic

speargun to implant the tags behind the mola's large dorsal fin. Although a number of molas were observed, approaching them close enough to tag was a real test of patience and stealth. At a price of US$3500 each satellite tag, her aim has to be true. So only sure hits were actually taken.

The BBC also documented the unusual cleaning stations of the sunfish. Its crew was on hand to tape the sunfish for the next instalment of the Planet Earth series. As this is the beginning of this kind of research, only a few tags were attached. Nothing else is known of their movements or life cycle of the tropical variety of the mola-mola.

Thys will travel to the Galapagos Islands in 2005 to tag topical molas there. It is hoped this research will be the start of bringing useful scientific and oceanic information about these rare creatures and also their midwater habitat . So six months from her repetitive plunges into Indo seas, Thys hopes to see the fruits of this cold and deep water work. When the tags pop up and start transmitting, new light should be shed on the odd mola-mola.

The Tags

Tim Rock attended the journalism program at the University of Nebraska - Omaha and has been a professional broadcast and print photojournalist for 30 years. The majority of those years have been spent in the Western and Indo Pacific reporting on environmental and conservation issues. He has won the prestigious Excellence in the Use of Photography from the Society of Publisher's in Asia. He also lists many other awards for documentaries, television shows including producer of ACE award finalist Aquaquest Micronesia, photography and writing. He works as a correspondent for numerous Pacific Rim magazines. He is the author of 6 Lonely Planet/Pisces series guides including The Diving and Snorkeling Guides to SouthAfrica and Mozambique, Chuuk-Pohnpei-Kosrae, Palau, Bali &