El sunfish, scientifically known as Mola molaOcean sunfish stands out among the multitude of marine species for its unmistakable appearance, colossal size, and curious habits. Considered the heaviest bony fish in the world, this inhabitant of temperate and tropical waters has fascinated scientists, divers, and hobbyists for centuries. In this article, you'll discover everything you need to know about the ocean sunfish: its unique morphology, habitat, behavior, reproduction, interesting facts, threats, and essential information to understand its life and importance in the marine ecosystem.
Characteristics and description of the sunfish (Mola mola)
El sunfish It is distinguished by its laterally flattened, almost oval or rounded body and a profile reminiscent of an enormous head with hardly any tail. Its width can equal or exceed its length when the dorsal and anal fins are extended, giving it a truly unique silhouette among fish. This marine colossus can reach up to 3,3 meters long and overcome the 2.300 kilograms, although the average is usually between 1.000 and 2.000 kg.
The sunfish's skin is another of its distinctive features. It lacks the traditional scales and, instead, has a smooth surface. thick, rough and very mucous, which can reach more than 7 cm thick especially in the ventral area. The color varies between brown, silver gray and white, with a typically lighter belly often decorated with irregular spots that serve as camouflage. Its body structure is supported mostly by cartilage, which, unlike other bony fish, gives it a light body and allows it to reach such impressive sizes.
Another unmistakable feature is the arrangement of its fins. dorsal and anal fins are long and pointed, reaching double the size of the fish. tail fin It is reduced to a rigid, rounded structure called clavus, fan-like, which replaces the function of the tail and acts as a rudder. pectoral fins They are small, rounded, and located near the head. Their mouths are small, narrow, and equipped with teeth fused into a beak-like structure, allowing them to tear apart jellyfish and other soft organisms.
El Mola mola It belongs to the order Tetraodontiformes, a group that also includes pufferfish, porcupinefish, and filefish, sharing characteristics such as fused teeth. Its spine is exceptionally short in proportion to its body, with very few vertebrae, and it lacks a swim bladder, which influences its peculiar swimming style. Its brain is tiny in relation to its body size, smaller even than one of its kidneys.
Regarding sexual dimorphism, there are no significant external differences between males and females that would allow them to be distinguished with the naked eye.
Geographic distribution and habitat of the sunfish
El sunfish it's a kind cosmopolitan Widely distributed. It is found in waters tropical and temperate waters of all the world's oceans and seas, being most abundant in the Atlantic, Pacific, Indian, and Mediterranean Seas. Genetic variations have been documented between populations in different oceans, but these differences do not prevent it from being categorized as a global species.
It usually lives open waters, pelagic zones and water columns from the surface to depths of 600 meters. Although they often associate with the surface, mainly to regulate their temperature and clean themselves of parasites, they spend much of their lives in epipelagic and mesopelagic zones, especially in search of food. They are commonly found near coral reefs, kelp beds, and kelp forests, where they frequently receive assistance. de peces cleaners.
They are usually attracted to waters with temperatures above 10 ºCProlonged exposure to colder waters can be fatal for the species. Their presence outside their typical habitat, such as in northern European waters, is linked to rising sea temperatures and climate change.
Behavior, habits and feeding of the sunfish
The behavior of the ocean sunfish is as peculiar as its physiognomy. It is considered solitary and slow-swimming, although capable of remarkable accelerations thanks to the size and power of its dorsal and anal fins. It usually swims calmly, moving by moving both fins from side to side in a rowing-like motion, rather than the traditional caudal flapping of other fish.
One of the most striking behaviors is its tendency to sunbathing on the surface. After diving to great depths to feed, it ascends and lies on its side, exposing as much of its body to the sun as possible. This habit helps it regulate your body temperature and facilitate the elimination of parasites thanks to the action of seabirds and fish. They have even been observed jumping out of the water as high as three meters to dislodge attached parasites.
The sunfish is generally harmless and not very scary to humans. Divers and sailors report curious encounters in which individuals of this species show a certain curiosity and docility, even coming close. However, due to its size and weight, it can cause unintentional damage to vessels if it crosses its path.
Their diet is based mainly on gelatinous zooplankton such as jellyfish, ctenophores and salps, although it also consumes crustaceans, cephalopods, larvae de peces, small fish and algae. Their diet is notoriously poor in nutrients, forcing them to consume large amounts of food daily. The Mola mola has the ability to spit and suck water through its small mouth to tear soft prey, while the pharyngeal teeth In their throat they break down the food before digestion.
In spring and summer, it tends to migrate to cooler latitudes to take advantage of the seasonal abundance of jellyfish and zooplankton, although it does not undertake large oceanic migrations like other pelagic species.
Reproduction, life cycle and development
Sunfish fry
The sunfish is oviparous and is characterized by being the most fertile vertebrate known currently. A single female can release up to 300 million eggs in each reproductive period, setting a record in the animal kingdom. The eggs, just 0,13-0,2 mm in diameter, are fertilized in the water and, after hatching, the young measure only 2,5 mm, they lack the typical adult form and have spines and caudal fins, resembling more juvenile puffer fish.
During the early stages, the fry usually gather in schools to protect themselves from predators. As they grow, they lose their spines and become solitary individuals. Ocean sunfish grow prodigiously: they can even increase in size. up to 60 million times from birth to adulthood. This intense development rate is supported by studies of captive specimens, where gains of up to 1,5 kilograms per day have been recorded in juveniles.
There is no precise data on their longevity in the wild, although in captivity they can reach up to 10 years of life thanks to the absence of predators and constant access to food and veterinary care.
Threats and conservation of the ocean sunfish
The ocean sunfish's colossal size and robust skin act as an effective natural defense against potential predators. However, sea lions, sharks, orcas and tuna They can attack adults or juveniles. Some species, such as bluefin tuna, prey especially on juveniles. Human predators have posed a considerable threat, both directly and indirectly, in recent decades.
El sunfish Figure as vulnerable species on the IUCN Red ListThe main risk is the accidental capture in trawls and longlines, where it can constitute more than 70% of by-catches in some fisheries. It is also intentionally hunted in regions where its meat, organs, and fins are considered a delicacy, especially in Japan, Korea and TaiwanIn the European Union, marketing and intentional capture are prohibited to protect the species.
La Marine contamination It's a growing problem: floating plastic debris, which resembles jellyfish, is accidentally ingested by ocean sunfish and can cause intestinal obstruction and mortality. Added to this are injuries from boat collisions and damage resulting from fin mutilation by fishermen. Beach alert for spiderfish, a danger hidden under the sand.
Currently, there are no specific, global conservation plans for this species, although some countries have implemented regulations and measures to reduce accidental capture and promote the safe release of these fish. Raising awareness about the ecological importance of the ocean sunfish is an ongoing challenge to ensure its survival.
Curiosities, names and popular culture of the sunfish
- Common and scientific name: In Spanish it is known as sunfish, due to its rounded shape and the reflection of its color on the sea surface, while in English it is called ocean sunfish (sunfish) for its fondness for sunbathing. Its scientific name Mola mola It comes from Latin and means "millstone" due to its texture and shape.
- Other names: It has various international names, including "maanvis" in Dutch, "peixe lua" in Portuguese, "poisson lune" in French, "Mondfisch" in German, "samogłów" in Polish, and "mambo fish" in Taiwan. In some regions of Spain, it is known as "mula" or "abarrotón."
- Dynamic coloring: The sunfish can change color from light to dark in seconds in response to stress or attacks.
- Parasitism: It is one of the fish with the highest documented parasitic load, reaching up to 60 species of parasites both on the skin and internal organs. Hence their behavior for removing parasites on the surface or by resorting to cleaning fish and birds.
- Interaction with humans: It is considered docile and safe for divers. Although its size may be impressive, it does not pose a direct danger to humans. However, it could cause accidents if a specimen jumps or collides with boats.
- Captivity: Keeping ocean sunfish in aquariums is an extreme challenge: they require huge tanks, specialized feeding, and must avoid injury from hitting the tank walls due to their clumsy movements.
- Jumping ability: There are records of specimens jumping up to three meters out of the water to free themselves from parasites.
- Historical references: The work of Cristóbal Medina Conde in the 18th century already accurately described the sunfish on the Spanish coasts.
El sunfish It is a biological jewel of the oceans, whose presence is vital in marine ecosystems by regulating populations of jellyfish and other gelatinous organisms, but which remains surrounded by mysteries and curiosities yet to be revealed.
With an imposing appearance and extraordinary lifestyle habits, the Mola mola It embodies the diversity and complexity of the marine world. Its survival depends as much on ocean conservation as on knowledge and respect for these unique creatures. Discovering and studying the ocean sunfish allows us to better understand the delicate balance of the oceans and the importance of protecting their biodiversity from growing threats.
