DESCRIPTION of SPECIES
Class: Osteichthyses (the bony
Order: Tetraodoniformes (trigger
fish, boxfish, porcupine fish, puffers)
Genus, Species: Mola
mola, Masturus lanceolatus, Ranzania
Presently, four distinct species are recognized within the family Molidae including: the common mola, Mola mola Linnaeus 1758, Mola ramsayi (Giglioli, 1883) the sharp-tailed mola, Masturus lanceolatus Lienard 1840, and the slender mola, Ranzania laevis Pennant 1776. Recent genetic work suggests there may be another clade of Mola spp. in Japanese waters (Yoshita et al., 2009; Yamanoue et al., 2010).
Throughout the world, a number of other intriguing common names
exist for ocean sunfishes including:
- Poisson lune (France) (meaning "moon fish")
- Schwimmender kopf (German) (meaning "swimming head")
- Putol (Philippines) (Bisaya dialect for "cut short")
- Manbo マンボウ (Japan)
- Toppled car fish (Taiwan)
- Bezador (Spain)
- Makua (Hawaii)
- Species & Distribution
- Early Life
- Diet, Size, Growth
- Parasites & Predators
mola (Roundtailed or Common mola)
most common of the ocean sunfishes is the Mola
mola. These fish, like all sunfishes, appear
as if their bodies have been somehow truncated
leaving them little more than a large head equipped
with long sweeping fins atop and below. The body
is less than twice as long as it is deep.
mola have a rounded tail, gritty sandpapery skin
covered with copious amounts of mucus. Typically
silvery in color with a slight opalescent sheen,
they can exhibit strikingly changeable spotty patterns.
They presently hold the record for the worlds
heaviest bony fish--a 3.1 meter (10 ft) long specimen
weighed in at 2235 kg (4927 lbs) (Carwardine, 1995).
lanceolatus (Sharp-tailed mola)
can also reach great sizes. As their common name
implies, sharp-tailed mola have a bit more to their
tail than Mola mola. Similarly colored to Mola
mola, they have a much smoother skin and produce
less mucus. Interestingly, sharp-tailed molas are
not consummate sunbathers and carry a smaller parasite
Wolfgang Sterrer |
laevis (Slender mola)
other molas, the slender mola never reaches more
than a couple of feet in length. These are the
most colorful and rarest of the ocean sunfishes.
They have a smooth and thinner skin and a vertically
Polynesians called these sunfish "King of the
Mackerels". It was seen as bad luck to catch
and kill Ranzania for such an act would render the
mackerel incapable of finding their way to the islands.
Mola ramsayi (Southern ocean sunfish)
Mola ramsayi looks very much like Mola mola however there are some distinct differences. Mola ramsayi has commonly known as the southern ocean sunfish for it was believed to only occur in the southern Hemisphere. This species however has been found in a number of locations in the northern hemisphere and as such its common name is no longer useful. The type specimen of Mola ramsayi is in England. It differs from the Mola
NOTE ABOUT NAMES
common name "sunfish"
is used to describe the marine family, Molidae, as
well as the freshwater family, Centrarchidae. The
common names "ocean sunfish"
and "mola" refer only to the family
Molidae and can be applied all three Molidae species.
word mola comes from Latin and means millstonein
reference to these fishes roundish shape. The
common name "ocean sunfish"
comes from the Mola molas habit of lying
atop the surface of the ocean appearing to sunbathe.
three species of sunfish are found in all tropical
and temperate oceans. With insight gleaned from
our incoming satellite tagging data and our
internet sighting form, we are beginning
to outline the seasonal distribution of ocean sunfishes
throughout the worlds oceans. And some interesting
patterns are beginning to emerge.
Molas produce an impressive number of eggs.
A 1.4m (4.5 ft) female was estimated to be carrying 300 million
eggs in her single ovary. (Larger Mola mola would
most likely carry even more.) 300 million is several orders
of magnitude greater than most other fishes and to date remains
the largest number of eggs ever recorded in a single vertebrate
at any one time (Carwardine, 1995). Needless to say, the
eggs are tiny and would fit into the size of this "o".
After hatching, the larvae expose their
affinity to their spiky puffer fish relatives by looking
more like swimming pincushions than wee molas. As they grow
the spines disappear, as do their tails. For more information
on larval development of molas see the Australian
Museum’s Fish Site.
upon By-the-Wind-Sailor (Velella velella
|Mola mola eat
a variety of foods, the most common prey items being
gelatinous zooplankton like jellyfish, Portuguese man-o-war,
ctenophores and salps. Squid, sponges, serpent star
bits, eel grass, crustaceans, small fishes and deepwater
eel larvae have also been found in M. mola guts
indicating that they forage both at the surface, among
floating weeds, on the seafloor and into deep water
(Norman and Fraser, 1949).
diet preferences of Masturus lanceolatus are
presumed similar to that of Mola mola. Bottom
dwelling sponges and annelids have been found in
the stomachs of youngsters (Yabe, 1953).
an assortment of crustacean, fish and molluscs including
myctophid larvae, hyperiid amphipods, crab megalops,
crab zoea and pteropods. Most feeding appears to
take place within 150m (500 ft) of the surface. (Fitch,
average size of an adult Mola mola is 1.8
m (6ft) from snout tip to the end of the "tail" fin
and 2.4 m (7 ft 10 in) between the tips of the dorsal
and anal fins. The average weight is up to 1 tonne
The heaviest mola on record came from Japan, was 2.7 meters (8.9 feet) long and weighed 2.3 metric tons (5,071 pounds). See http://news.nationalgeographic.com/news/2003/05/0513_030513_sunfish.html Before this discovery the largest Mola mola ever recorded weighed 2235 kg (4,927 lbs) and measured 3.1 m (10 ft) from snout tip to "tail" fin, 4.26 m (14 ft) from dorsal fin to anal fin tip. That animal was struck by a boat off Sydney, New South Wales, Australia in September, 1908 (Carwardine, 1995).
No data exist on how fast mola grow in the wild but one individual in captivity at the Monterey Bay Aquarium gained 364 kg (800 lbs) in 14 months. Fattened up on a diet of squid, fish and prawns, this fish had to be airlifted out by helicopter and released into the bay after outgrowing its tank. (Powell. D. 2003 A Fascination for Fish, UC Press/Monterey Bay Aquarium Series in Marine Conservation.)
The longevity of molas in the wild is also a mystery although Kamogawa SeaWorld in Japan housed the same individual for more than10 years in captivity. (Nakasubo et al. 2007, Growth of captive ocean sunfish, Mola mola Suisan Zoshoku 55: 403-407. A growth curve derived from repeated measurements of captive individuals estimated animals with a total lenth of 3m would be approx. 20 years old (Nakatsubo, T. 2008, A study on the reproductive biology of ocean sunfish Mola mola. Dissertation. International Marine Biological Institute. Kamagawa Sea World, Japan. Liu et al 2009 examined vertebral growth rings in Masturus from Taiwan and estimated lifespan of individuals greater than 2 to 23 years for females and 1-16 years for males.
Mola come in a variety
of gray and white patterns with some sporting your basic gray motif
while others go for the more polka-dotted appaloosa style. Many
also have a slight iridescent sheen. Certain geographic areas may
have discrete color patterns—for example
the mola in Bali are typically darker than the ones off Southern
California but these data are still preliminary.
Mola are capable of color changes
particularly when stressed or under attack from a sea lion or other
predator and can turn from light to dark within a matter of moments.
Lepeoptheirus sp. or Caligus sp .
Click for detail. Can you count them all? Photo courtesty Chris Potgieter
Sept 30,2007 at Crystal Bay, Lebongang,
Bali Dive depth
was 45m at the cleaning station.
Removed from the inside of a Masturus lanceolatus in Hua
Lien Taiwan--supposedly 1 in 100 Masturus there have these tumors.
Since parasites often
sport multiple hosts, they can offer valuable insight into mola
interspecies associations. For instance, one mola parasite
is the larval stage of a shark tapeworm so at some point the mola
most likely falls prey to shark enabling this parasite to complete
its lifecycle. For a list of known parasites of the family Molidae
The common sunfish, Mola
mola, are infamous for their impressive parasite load. Some
40 different genera of parasites have been recorded on this species
alone. In fact, even their parasites have parasitesa fact
reminiscent of Jonathan Swifts quip:
observe, a flea
fleas that on him prey;
have smaller still to bite em;
And so proceed
are not as heavily parasitized as Mola mola. And while they
dive to great depths, even greater than those of the Mola mola,
they do not appear to engage in sunbathing to the same degree. Little
is known about the parasites of Ranzania, the slender mola.
Mola skin 88x
Mola scales 176x
Sea lions (Zalophus
Bat stars (Asterina
miniata) consuming dead sunfish
There's safety in great size for the ocean sunfishes but on the
road to largess, they are open to many dangers. Bycatch
through fishing certainly takes a toll on mola populations. And
parasites presumably claim quite a few
lives as well. Other predators include orcas (Gladstone, 1988) and
During the fall months
in Monterey, California, sea lions can be seen ripping the fins
off sunfish and slamming the dismembered bodies against the sea
surface. Presumably this action helps the lions tear through the
molas skin which is leathery tough and several centimeters
thick in places. However, after tossing the bodies through the air
for several minutes, the lions often simply abandon their prey.
Tragically the hapless, finless molas unceremoniously sink
to the seafloor and are consumed slowly by bat stars.
is known about predation on Ranzania. However an adult
female (335 mm in total length) was found in the stomach of
a marlin off Hawaii. Numerous
Ranzania youngsters have also been found in the guts of
mahi mahi Coryphaena hippurus. (Sherman, 1961)