The family of Ocean Sunfishes (“Family Molidae”) currently comprises five recognised species in three groups or “genera” (singular: genus).
The famous ocean sunfish, Mola mola, belongs in the genus Mola, together with its two sister species; the lesser known Mola alexandrini, and a brand new species only formally described and named in July 2017, Mola tecta.
The two other genera of sunfish each have only one species in each. Masturus contains the species Masturus lanceolatus and Ranzania contains Ranzania laevis.
Common name: Bump-head Sunfish or Giant Sunfish
Scientific name: Mola alexandrini (formerly Mola ramsayi)
Reaching sizes of over 3m long, 4m tall and weighing over 2000kg this species can certainly be an impressive sight.
Thanks to Dr. Etsuro Sawai from Japan, we now know that it is Mola alexandrini that holds the title of World’s Heaviest Bony Fish – this coveted title previously thought to be held by the infamous Mola mola.
For many years Mola alexandrini had the common name “Southern Sunfish” due to the misconception that they resided only in the southern hemisphere. More recently this species has been found across the northern hemisphere as well, indicating its distribution is much wider than originally thought. This is why the common name of this sunfish was changed to “Bump-head Sunfish”, which refers to its shape as it gets larger.
For many divers this fish is on the ‘bucket list’, and one of the best places in the world to witness these crazy looking creatures are the islands of Nusa Penida, Bali, Indonesia.
Although this particular species is the most commonly seen in Bali waters, we now have evidence that they are not the only one! So far we have evidence of two species of sunfish in the waters of Bali, although Mola alexandrini is undoubtedly the regular visitor.
Common name: Ocean Sunfish or Common Mola
Scientific name: Mola Mola )
The iconic Mola mola is the best known of all the sunfishes. For many in Indoneisa, ‘mola-mola’ simply means ‘sunfish’ – any sunfish. From the dawn of tourism in Bali everyone believed that the Bali sunfish were Mola mola. However recent genetic analysis of sunfish from Nusa Lembongan have shown that the Bali sunfish are in fact Mola alexandrini (Sawai, Yamanoue, Nyegaard & Sakai. 2017).
Mola mola is widely distributed throughout all temperate and tropical waters of the world – including Indonesia. While they are without doubt present in Indonesian waters, as verified through photos from areas further towards the Pacific, they do not seem to frequent the Bali reefs; the extensive archive of mola photos collected from around Bali in our Sunfish Photo ID Catalogue, does not yet include a single Mola mola!
Common name: Hoodwinker sunfish
Scientific Name: Mola tecta
Incredibly, this sunfish species is brand new, only described in July 2017 (Nyegaard et al. 2017)! Despite growing to a size of at least 242 cm in total length, it managed to hoodwink science until genetic tools and an extensive search revealed its identity and distribution: the cold temperate waters of the Southern Hemisphere.
At smaller sizes, all the Mola species look frighteningly similar, however, as they grow their species specific characteristics become pronounced. Luckily, the Hoodwinker reveals its identity if only one looks closely enough: check out the clavus and look for a small indent in the clavus edge; here you will see a small piece of soft skin, dividing the clavus into a smaller upper and larger lower part. But be careful, sometimes the Bali sunfish (Mola alexandrini) have nicks and injuries to their clavus edge, which can look similar! They may also have a similar piece of soft skin dividing the clavus into two parts, however it is not as pronounced as on the Hoodwinker, and is usually only visible when the sunfish moves its back end.
At larger sizes, Mola alexandrini and Mola tecta are very easy to tell apart: Mola alexandrini develops a lumpy, rounded appearance with a head bump and a ‘chin’, whereas Mola tecta stays slim with an elongated appearance and a very pronounced ‘eye brow’.
Unfortunately you are highly unlikely to spot a Hoodwinker around Bali; to see one, you need to don a dry suit and go diving off New Zealand – the further south the better! Or jump in the ocean off the southern half of Chile, where divers reportedly see small ones quite regularly during summer months.
Common name: Sharptail sunfish
Scientific Name: Masturus lanceolatus
This fish gains it name from the shape of its back end, which is distinctively pointed, and makes for fairly easy identification. Be careful though because the pointy bit can vary from long and obvious to short and subtle.
The top right photo is the first image we received of a Masturus swimming in Bali waters! It was taken in July 2017. Thanks to the lucky videographer Adi Huang, who confirmed for us that this fish was swimming off Nusa Penida.
The bottom right photo shows the pointed ‘tail’ more clearly, illustrating just how pronounced the protrusion can be.
The Sharptail sunfish is a tropical species. Photos from both fishing and stranding events across Indonesia and Papua suggest this species has a broad distribution in these waters and is relatively common.
Up until 2017 there was no photographic evidence that this species visited Bali, however, the Ocean Sunfish Research Photo Identification catalogue now has three photos of a Masturus seen swimming in Bali waters! Clearly Masturus lanceolatus is not as enamored with the area as Mola alexandrini but to have evidence that they are in fact visiting the Bali reefs at all is incredibly exciting and fascinating. We hope there will be more Sharptail photos coming our way in the future.
Common name: The Slender sunfish
The Slender Sunfish is the smallest of the four sunfish species, growing no longer than 1m in length. It has a beautiful silver skin with subtle colours with white stripes and dots, but is unfortunately rarely encountered by scuba divers.
Little is known of this species, but it is thought to be distributed in all tropical waters, sometimes (perhaps seasonally) venturing into more temperate waters. They may not be well suited to colder temperatures; mass stranding events along the coasts of South Africa and Western Australia are thought to be linked to temperature shocks.
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