It is common for fish to swim in the water, and it is not surprising that the ancients came up with the four-word motto "like a fish in the water" very early. But things in the world are not static, and there are many species that have evolved over a long period of time to form their own unique way of life. Today, I will take a look at the protagonist of this issue's story, a small fish that can move freely in amphibious amphibious waters - mudskippers.
Speaking of the origin of the bomb scribbling one, it is necessary to mention a set of maps drawn by the Qing Dynasty painter Nie Huang, the "Sea Fault Map" [1]. "Jumping fish, raw Fujian and Zhejiang sea tu." Sex is good at jumping, so it is known as jumping fish, also known as muddle. The author went straight to the point and introduced the origin of the name "jumping fish", that is, fish bouncing on the beach. The book once described the mudskipper as "angry as a frog, with a mouth like a fish, a backstab like a flag, a belly like a flag, brown and green."
Introduction to mudskippers in "Sea Fault Map| Literature[1]
Angry frog-like mudskippers | Musubk/Flickr
After introducing the origin of the name of the mudskipper, let's talk about its basic biological information. Mudskippers are small fish of the family Goby in the order Perciformes, with adult bodies about 80–120 mm in length. There are 6 species distributed along the coast of China, namely mudskippers (mudskippers, large-fin mudskippers and silver-lined mudskippers), large mudskippers (large mudskippers) and green mudskippers (big green mudskippers and green mudskippers) [2]. They usually live in brackish waters in estuarine and mangrove areas, but also in coastal sediment geology of tidal flats, intertidal and low-tide waters. Whenever the tide recedes, people can often see the cool and heroic posture of mudskippers jumping from the water. With their unique adaptation mechanism, they break through the environmental limitations of amphibians and become the most representative fish in intertidal ecosystems.
Speaking of which, many people will have questions, they have no lungs, will they not die without leaving the water environment? How can they jump so high and even climb trees? Don't the larvae in their burrows drown at high tide? With these questions in mind, let's take a look at the special physiological structure and life behavior of mudskippers.
First, why can mudskippers leave the water to live?
Before we get into this, we should first understand why they leave the water, which is closely related to its food composition. Mudskippers are plant-based eaters, preferring to eat organic matter from benthic diatoms, blue-green algae, and mud coats, and sometimes sand silkworms and copepods. Many of these foods are found in tidal flats, swamps or other wetland environments, which forces mudskippers to leave the water to forage on land, and this food-chasing instinct allows mudskippers to slowly evolve a set of mechanisms to adapt to land life.
Some people have vividly compared mudskippers to fish carrying oxygen tanks ashore. That's right, because before the mudskipper is ready to go ashore, it can open its mouth and suck in a mouthful of water to store in the gills, and after leaving the water, it can suck in the air and breathe through the water in the gills. This process, like our deep breath and then slowly exhaling, can help mudskippers extend their life on land and thus achieve their foraging goals. In addition, the skin and oral mucosa of mudskippers can also be used to absorb oxygen from the air for the purpose of aiding breathing [4]. It is with these special breathing skills that mudskippers can move freely and freely in amphibious environments.
The swollen gills after water storage | Berniedup/Flickr
Second, why can mudskippers jump and climb?
I don't know if you have heard the idiom of "asking for fish from the wood"? It means to find fish along the trunk of a tree, and people use it as a metaphor for something that goes against the laws of things and cannot succeed. But the mudskipper is an exception, not only can it leave the water to live, but it can also crawl, jump and even climb trees, thanks to its fins. [5] The pectoral fins of mudskippers are arm-shaped, much like the two feet of higher animals, and play a good supporting role. When jumping, the pectoral fin of the mudskipper supports the body, and then bends the tail fin and slaps the ground or the surface of the water hard to obtain enough reaction force to push it to jump. When climbing trees, it mainly grasps the trunk with its pectoral fin, and the ventral fin clings tightly to the trunk like a suction cup, providing extra adhesion so that it can leisurely climb towards the tree.
Jumping mudskipper | Charles Lam/Flickr
Mudskippers take a nap on the branches | Pacific Klaus/Flickr
Third, what are the special habits of mudskippers?
In addition to the characteristics mentioned above, mudskippers also have special habits in courtship, burrowing and juvenile rearing. Let's first look at its courtship behavior, every breeding season, the male fish on the mud after the low tide will show their vitality in front of the object of their choice. If it does not have much effect, it will also adopt a series of tricks such as hunchback, vertical fins, and swinging its head and tail, just to attract the attention of females, but also to compete with other males for resources. After this process, if there is a female fish willing to enter its burrow, it is done.
The talent display of male mudskippers | Berniedup/Flickr
Finally, let's talk about the habits of mudskippers in digging holes and raising juveniles. On the mud mudflat where mudskippers inhabit, we will see many holes, which is the entrance and exit of the mudskipper cave. These caves are usually in the shape of a "Y" or "U" shape, which mainly performs the functions of avoiding predators and laying eggs and raising children. The eggs laid by mudskippers will cling to the top of the nursery, and they must directly suck oxygen through the air, and the oxygen in the hole will be exhausted at high tide, which will seriously affect the normal development of the larvae. Therefore, during the nursery stage, the mudskipper parents will take turns to swallow air outside the hole and inject it into the nursery. Since the top of the nursery is rounded, the air here will gradually form an air bubble, and as the gas continues to increase, the bubble will cover the entire nursery, thus meeting the respiratory needs of the larvae [6].
Literature on fertilized eggs in large mudskipper cave structures and spawning chamber|s[6]
1. The main opening is open 2. The main opening is closed 3 Fertilized eggs at the top of the spawning chamber 4. The resin model shows the cave structure
After reading the above introduction, I think you can't help but sigh: mudskipper fish is really the most outstanding explorer and doer in fish. Without enough courage and a yearning for a new environment, mudskippers may never appreciate a more colorful world beyond the deep waters.
Author:Wei Kai
bibliography:
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Wu Hanlin,Zhong Junsheng. Fauna of China-Teleost fish-Perciformes-5-Gobies suborder[M].Beijing:Science Press,2008:693-718.
SUN Jianyong. Fish carrying "oxygen tanks" ashore[J].2018,24:21.
[4] G. Zaccone, E. R. Lauriano, G. Capillo.Air- breathing in fish: Air-breathing organs and control of respiration Nerves and neurotransmitters in the air-breathing organs and the skin[J].2018,120(7)：630-341.
[5] C.M.Pace , A. C. Gibb.Mudskipper pectoral fin kinematics in aquatic and terrestrial environments[J].2009,212:2279-2286.
Zhang Qiyong, Hong Wanshu, Chen Shixi, et al. Study on spawning habit and natural fertilized egg hatching of intertidal mudskipper[J].2006,25(5):68-73.