The sunfish or mole: fish that can weigh up to a ton!

The sunfish diet has long been a mystery. Today, its longevity as its reproduction keep their dark side in this species with the allure prehistoric. Close-up on the pier, a growing animal all his life and which is unlike any other.

The sunfish, round like a grindstone

The sunfish (Mola mola) belongs to the order Tetraodontiformes and to the family of molidated. Its scientific name comes from the Greek mola – millstone – in reference to the round shape of the animal. In addition to Mola mola, there are three other species of molids in the world:

  • The sunfish truncated (Ranzania laevis) is much smaller (size 80 cm). It lives in the Mediterranean and the tropical Atlantic to the British Isles;
  • The sunfish lancéolé (Masturus lanceolatus) strongly resembles the common sunfish. Its distribution area is limited to the tropical Atlantic to the Azores and Madeira;
  • Sunfish Ramsay (Mola ramsayi or Mola alexandrini) can reach 3 meters long, like the Mola mola. This extremely rare species frequents temperate and tropical waters of the southern hemisphere.

The incomparable physique of the pier

The body almost circular sunfish displays a rather ovoid appearance when viewed from the front and flat in profile. The animal has a caudal fin atrophy, two small pectoral fins and a triangular and symmetrical dorsal and anal fin. Molidates appear to have no scales but they are actually present in the form of small spikes non-nested. The skin of the sunfish, more or less speckled, varies from silver to white through shades of gray bluish or beige. Its fins are generally darker and its belly paler. Like all tetraodontiformes, its teeth and jaws are fused into one beak formed of two dental blades.

The sunfish grows all its life

The Mola mola measures on average 1.80 m long and up to 3 m high. Its weight can exceed the tonne in fact the most bony fish heavy of the planet. Its exceptional size can be explained by continuous growth as the pier grows until its death. Theabsence caudal fin requires it to use the dorsal fin and anal fin to move. This particularity gives it a slow swimming but does not prevent it from suddenly propelling itself in the event of a threat. Despite its impressive dimensions, the pier is harmless and presents no danger to humans. This placid colossus peacefully crosses the oceans in search of food and a deworming session.

The mole is infested with parasites

The thick, rough dermis of the mole covers tiny tubercles and a mucus abundant in which come to take refuge a considerable quantity of parasites. To get rid of it, the animal approaches the coasts, reefs and fields of algae to let itself be deloused by the young. Pisces (common wrasse, black-tailed crenilabra, sar …) which also clean its wounds and his dead skin. The Mola mola also takes long and regular sunbaths on the surface of the water in order to attract birds fond of parasites. It is also seen performing very high leaps in the air or diving to great depth (600 meters) to chase some of its hosts.

Sunfish thrive in the Mediterranean

The sunfish lives in all seas hot (with a temperature above 10 °), whether tropical, subtropical or temperate. It is frequently found in the Mediterranean – from the French coast to Portugal in winter – where its favorite dish abounds: jellyfish. In Atlantic, the mole moves from Scandinavia in Canada to Argentina in summer. In the Peaceful, it is observed in Asia, Australia and America. Rather adept at coastal waters, the animal also frequents the deep sea where it lets itself be carried by the hot currents.

Double ration of jellyfish for the pier

The diet of the mole consists mainly of jellyfish. Considering the low nutritional value of these soft-bodied marine species, the animal consumes a considerable amount and supplements its meals with small fish, squid, crustaceans, elvers (eel fry), sponges and other zooplankton. Its round mouth allows it to suck up its prey which it shreds with its pharyngial teeth, located in the throat.

The thorny larvae of the sunfish

The breeding conditions of the sunfish remain little known. However, we know that moles congregate in the various oceans of both hemispheres. In spring and in open water, females lay up to 300 million of eggs fertilized by the sperm of the male when they are ejected. The larvae are barely 2.5 millimeters in size and only a handful of them will escape the predators. Survivors develop in two phases: they first lose their caudal region and then overlap withthorns which serve in particular to protect themselves. At this point we call them fry. As they grow they will lose their skin hedgehog and experience rapid growth: some specimens indeed reach a size of 1.80 meters in fifteen months.

Nets: a danger for the pier

Due to its impressive dimensions, the adult sunfish possess few predators. In contrast, juveniles are easy prey for sharks, killer whales and sea lions. The main threats to the species are nets used by bottom trawling and where many moles perish. Their numbers show a decline of 10% per decade according to the International Union for the Conservation of Nature (IUCN) which, as such, classified the sunfish in the “vulnerable” category. If its longevity in the wild is not known, it is more than 10 years in captivity.