May 18 (Lunar calendar: March 29), 2023 Thursday | Dawnxisoul393art
A series of "Hong Kong hot topics" and the "most" of the ocean...
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The most spawning marine creature in the ocean, Mola (sunfish)
- From the emergence of a fish suspected to be a Mola (sunfish) in the Tuen Mun River, Hong Kong
On the morning of April 25 this year (2022), a big fish was frightened when swimming in the Tuen Mun River in Hong Kong. Its fins are exposed in the water and have been mistaken for sharks or dolphins. The first time the fish were found was at about 7:50 a.m. that day. A neighborhood on the Tuen Mun River saw a large fin protruding from the water and sliding. During this period, a nearby boatman found that a large marine fish had strayed into the river by mistake. He also drove the boat to escort it and tried to guide it back to the sea. As soon as the incident spread, the relevant short film quickly spread widely on the Internet, and some people called the police. After observing the characteristics of this big fish, diving enthusiasts and nearby boatmen all judged that this big fish looked like a rare deep-sea fish in Hong Kong - the Mola（sunfish). Fish in the Tuen Mun River in Hong Kong immediately became a hot topic in Hong Kong.
Zhuang Dihua, President of the Hong Kong fish society, said that after watching the video, he believed that the big fish was a Mola with a length of about 2.5 meters. This kind of fish usually inhabits a depth of 100 to 200 meters in the sea, and it is suspected that it strayed into the Tuen Mun River in Hong Kong by mistake. There is a kind of fish with a strange shape and huge body shape in the ocean, which looks like the back half of the body has been cut off, with a head but no tail. Some fishermen often call this strange behemoth "giant sea monster", "monster" and so on. Mola is widely distributed in temperate and tropical waters all over the world. It is the largest known bony fish in the world. As a super-large marine fish species, Mola can grow to 3-5 meters long and weigh 2000-2500 kg. Mola, with a round head, small eyes, and small mouth, is extremely wide, flat, and huge. It can be called one of the strangest fish in the world.
Due to its extremely flat body, which is higher than wide, it looks quite strange at first glance. When it swims in the sea, its tall dorsal fin emerges from the water, which is often mistaken for a shark. Mola may be a strange shape, which makes it difficult to maintain balance in the ocean and often overturn on the sea. Therefore, fishermen in some parts of the world think that catching Mola is an unlucky thing. When molas hatch from fertilized eggs, their body length is only about 0.25 cm. After about 5 years of growth, molas can grow from 0.25 cm in infancy to 3-5 meters in adulthood, and their weight reaches an amazing 1.5-3.5 tons. It is about a 60million times higher than that in the juvenile period. In addition to its strange appearance, Mola also has very strange habits. It often floats sideways for a long time without moving. It looks like it is lazily basking in the sun. This is why the fish is also known as the "sunfish".
Biologists suspect that this behavior may be a way for sunfish to regulate body temperature. There are a large number of parasites on its body surface, or it may be conducive to small fish or seabirds to peck the parasites attached to it. Molas have no ventral fins or caudal fins and have a pair of huge and towering dorsal fins. In the ocean, they only rely on the incitement of dorsal fins to control the direction. Sometimes they are even lazy to wave and drift directly with the waves. The maximum swimming speed of Mola without a tail fin is only 3.6 kilometers per hour, and the swimming mode is particularly clumsy. It is impossible to turn, and it is even more difficult to turn around. Poor swimming ability has been the fatal defect of molas. Coupled with their docile temperament, molas, although they have a huge body, lack sufficient self-defense ability and escape skills, and are often attacked by large ferocious marine creatures such as sea lions, sharks, whales, and so on.
Mola is the spawning champion of marine organisms. Female Mola can lay 300million eggs at a time. When the breeding season comes, male molas will look for an ideal place on the seabed, and use their fins to build a concave "production bed" of sediment to lure female fish into spawning. Interestingly, the female just cares about breeding and then leaves without caring after spawning. From then on, the male fish needs to take the responsibility of protecting eggs and raising children until the young fish leave. Although a female spawns a large number at one time, the whole population of sunfish is not optimistic. Most of the eggs produced by female Mola are floating eggs. Some eggs die because they cannot be fertilized, and some eggs will be eaten by other fish.
Of the 300 million eggs, only about 30 may eventually grow into big fish, with a success rate of less than one in a million. Even the lucky hatchlings have a relatively small chance of surviving. Lack of maternal love in childhood, often harassed by predators due to their small size, may also die due to poor sea conditions, poor self-defense ability in adulthood, and the risk of being caught by humans. The growth history of Mola is a rocky one. Fortunately, because of the strong fecundity of Mola, the species of Mola can continue. Molas are distributed in almost all the oceans in the world, but there are not many sea areas where we can see a large number of molas, and there are even fewer opportunities to see molas in Hong Kong.
Original by Dawnxisoul393
（1003w）
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