Lead
In the deserts of North America, there is an amazing fish, but this fish does not live in water.
The fish is yellowish-brown in color and resembles fish in both appearance and size, but it lives on sandy ground and only takes refuge in small pools to rest in extreme weather.
This fish is called the medaka, and their ancestors have lived in the desert for 50,000 years, and after 50,000 years of evolution, their living environment in the desert has not been greatly affected, but has become more powerful.
However, the number of medakas is very small, less than 100, and they are now threatened with extinction.
Why is this fish threatened with extinction when it can survive in such an arid and hot desert?
And how can we protect the population and living environment of this fish?
1. The living environment of the medaka.
In the arid deserts of northwestern North America, there is a very peculiar fish, the medaka.
The number of medaka is very small, according to a survey conducted in 2017, the number of medaka is less than 100.
The medaka lives mainly in the Mojave Desert in California, one of the driest places in the world, with an average annual rainfall of less than 100 mm.
Many people will be surprised that this fish lives in such an arid desert.
In fact, the living environment of the medaka is not this desert, but some small pools in this desert.
These small pools are often formed by extreme weather or the melting of snow falling from the mountains, but the water in these small pools is very small, and some are only the size of a puddle of muddy water.
And the water in these small pools is often highly concentrated brine, and some even have a salinity of up to 13%.
This salinity is almost four times that of seawater, and in the summer, the water in these small pools becomes salinity as much as 30% as it evaporates.
However, despite this, the medaka can survive in this extremely high concentration of salt water, and can even swim freely in the water like a fish, which is why people call this fish "medaka".
How does this amazing fish survive, especially now that the environment in this desert is basically unsuitable for other fish, but what is the fish that can survive?
In fact, the ancestors of the medaka were not the fish that lived in this desert, but the sturgeon fish that lived in the inland seas of North America about 50,000 years ago.
This sturgeon was very common at the time, but as geological changes caused the inland sea to dry up, the sturgeon was soon in danger of extinction.
But by that time, some sturgeon had evolved the ability to survive in water with higher salinity, so they survived in small pools in the inland sea.
Due to their small numbers, their living environment in the inland sea was not greatly affected, but they also evolved a more powerful survival ability, and eventually formed the current medaka.
2. The survival method of the medaka.
It is often said that "things gather by like, and people are grouped", and there is a corresponding truth in nature.
Organisms in nature tend to gather together according to their living environment and living habits, thus forming an ecological circle.
There are not many creatures in this biome, but they are all very suitable for living in this biosphere, and the same is true of the place where the medaka is located.
Although the water in the small pools in the desert where the medaka is located is highly concentrated, the salt concentration in it varies, which also leads to the different numbers of fish in these small pools.
Small ponds with high salinity tend to have fewer fish due to excessive salinity, and the number of fish often does not exceed 100.
In small pools with low salinity, there are also small pools where hundreds of fish live, although there are few fish that survive.
The number of medakas is also more or less affected by the surrounding environment, but in general they are very small, which is why people only discovered them in 2017.
Although small in number, this amazing fish has a very strong ability to survive, and their cell membranes can conserve water, making it adaptable to high salt water.
In addition, their cell membranes also have the function of secreting urea, which can not only maintain their own osmotic pressure, but also conserve water, which is very important for organisms in such arid deserts.
At the same time, their kidneys are very well developed and are able to excrete excess salt, so even if they no longer swim in the water like fish, people can tell that they are fish in size.
And their gill slits are gradually degraded and replaced by vegetative, film-type gills that are better adapted to such arid environments.
The living habits of medaka are also very peculiar, because their living environment is a small pool with the change of salinity gradually increases with the season, so they will gradually adapt to the increase of salinity in the small pool, and eventually can survive in high salinity water.
At the same time, medaka will forage for insects and plants that have landed in the desert at night, and during the day, they will take refuge in the muddy water in small pools to escape the scorching sun.
The fact that medaka can survive in this environment also shows that the adaptability of creatures in the desert is very strong, and their ability to evolve is also very strong, which is also the wisdom of creatures in nature.
3. The extinction crisis of the medaka.
Nowadays, the small pools in the desert where the medaka are located are gradually decreasing, and the salinity in these small pools is gradually increasing.
This is due to the overexploitation of natural resources, the excavation of oil and groundwater in the desert, which has gradually reduced the water in the small pools in the desert and increased the salinity.
In addition, people have also carried out breeding and animal husbandry on the land in the desert, which has gradually deteriorated the already scarce living environment.
In addition, the rapid exploitation of natural resources has turned the water in the small pools in the desert where the medaka is located has turned into dry soil, and many medaka have died as a result.
Nowadays, the population of medaka is getting smaller and smaller, which also makes people realize that the living environment in the desert where the medaka live is so fragile, but because the living environment is so harsh, it is impossible to migrate them to other environments.
However, in order to protect the medaka, scientists have designed an artificial fish tank to provide a living environment for the medaka, which can not only maintain the survival of the medaka, but also allow the number of medaka to gradually increase.
However, this artificial fish tank is very expensive, and it also takes up a lot of space, and it is a very long process to get these medaka fish to adapt to the water in the artificial fish tank.
Therefore, there is still a long way to go to protect medaka, and more scientists and people who love nature are needed to help.
epilogue
The story of the medaka tells us that there are still many unknown creatures and ecosystems on Earth, and that humans not only need to know more about the natural world, but also need more protection measures.
The survival of living beings is closely related to the environment, and human beings, as creatures on the earth, should also be more cautious about the use and protection of natural resources.