DID YOU KNOW THAT...
... Sunfish is the biggest of the bony fish, reaching 3.3 metres and 2,300 kilos?
Did you know that females can carry up to 300 million eggs? Discover how this animal is in the Oceans tower of the Oceanogràfic.
Distribution: temperate and tropical seas.
Measurements: reaching 3.3 metres and 2,300 kilos.
Food: plankton jelly, squid, sponges, crustaceans and small fish.
Special characteristics: these fish have no scales but are instead covered with a mucus gel that serves as protection.
Sunfishes (Mola mola) are pelagic (they live in the open sea), native to temperate and tropical waters, and feed mainly on plankton jelly, especially cnidarians such as Portuguese man-of-war, ctenophores and tunicates. They may also feed on squid, sponges, crustaceans and small fish. When swimming near the surface its dorsal fin can be seen, and may get confused with the dorsal fin of a shark.
The Sunfish at the Oceanogràfic are fed on squid and a gelatine preparation to keep them well hydrated. In the wild they feed on jellyfish, which have a high water content.
Adult Sunfish can exceed 3 meters in size and reach more than 2 tons in weight. The brain of a sunfish is quite small relative to their body size. A 200kg individual may have a brain of just a few grams.
Despite being large fish, they are completely harmless. In the natural environment they may have large numbers of parasites. They get rid of them thanks to the help of certain sea birds that perch on them while they lie horizontal and static on the water's surface. Their swimming is somewhat slow and awkward, though when required they can go faster to escape threats.
These fish have no scales but are instead covered with a mucus gel that serves as protection.
These fish are closely related to other fish such as trigger fish, box fish or porcupine fish. While it is true that their morphology seems quite different, their relationship is more noticeable in the way they swim, and especially in the morphology of the mouth, more specifically in their dentition. They all belong to the Tetraodontiformes order, characterized by the absence of scales or their modification into bony plates or spines. Their mouth is small, with strong jaws, where the maxilla and premaxilla are fused together. Their teeth are strong and can be separate or fused into plates.
The ocean sunfish has no commercial interest. Its meat does not taste good, and it is one of the fish with most parasites, both outside and inside. Sometimes they get caught in fishing nets.
Origins of their names
Interestingly, in Spanish the sunfish is called "pez luna", meaning "moonfish." In Spain there is a legend that fishermen were fishing at night and came across one of these animals, awkwardly swimming close to the surface. They confused it with the reflection of the moon in the water. It’s been know as the moonfish ever since.
The scientific name of this fish (Mola mola) is due to its resemblance to the stone that was used in mills for grinding grain, the "millstone".
The sunfish is registered in the Guinness Book of Records for its extraordinary feat of being able to lay 300 million eggs in one time. This relates to a theory developed by ecologists called "r- selection and K-selection". This theory puts forward two different types of reproductive strategies depending on environmental conditions. The habitat of a species determines the strategies used to perpetuate itself. Animals that are adapted to life in harsh environments are known as r- strategists, while those living in stable habitats are K-strategists.
r -strategists tend to have many, very small offspring that mature rapidly. They offer no parental care and reproduce just a few times throughout their lives (semelparous).
K-strategists on the contrary have few young, which are large and slow to mature and are given parental care. These species can reproduce several times throughout their lives (iteroparous).
The sunfish is a great r-strategist. Living in an environment as unpredictable as the sea, it finds it difficult to find mates and the chances to reproduce are very few.
Discover the sunfish in the Oceans facility of the Oceanogràfic.
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