25 ° C, the "key password" of the breeding of Chinese 育

When it comes to the rare and unique fish in the Yangtze River Basin, the first thing everyone thinks of may be the white -fired dolphin (white fin dolphin) that has been announced for extinction, "functional extinction", and the national first -class protection of the Yangtze Rolls. I have heard of it but I don't know much about it.

But in fact, my country 国, as a key point of protecting wild animals in China and giant pandas in the water, we should pay more attention to it.

"Noble in the Water" China 族

Chinese 我 is a kind of unique catfish living in our country. They are large individuals. Adults can reach 4m in length, weigh more than 700kg, and have a life span of 40 years. It is the largest and longest life of freshwater fish.

The mouth of Zhonghua's mouth is sharp, with small toothless mouth, and there are four tentacles in front of the mouth, which is used to find vertebrates and small fish on the bottom of the water. The eyes are small, with a crescent -shaped water spray hole on both sides of the head. The tail fin is crooked. The upper lobe is particularly developed and the body is oval -shaped.

The particularly noticeable characteristics of Chinese crickets are that the body is covered with five vertical large -scale bone plates, which makes it look very prestigious, but it only uses plankton and plant debris. "Sven Fish", inhabits the bottom of the Great River and the bottom of the offshore. So why is Chinese crickets "nobles in the water"?

First of all, my country ’s pupae is a key lead in protecting wild animals in China. The number of existence in the wild is scarce. It is known as the“ panda in the water ”, which is“ valuable ”.

Secondly, China ’s cricket has a huge shape and is known as the“ King of the Yangtze River Fish King ”. It has the habit of migrating the migration and migration of the migration.

Furthermore, Chinese 球 is the oldest vertebrate on the planet. It is a living stone that lives in the same period as dinosaurs. It is currently distributed in the Yangtze River Basin in my country. It has high scientific research, medicinal and ornamental value. "".

China ’s“ expensive ”occupies an extremely important position in classification. It is an important reference for studying fish evolution. It has important scientific value in studying biological evolution, geological, landforms, sea invasion, and sea retreats. And difficult ecological, social, and economic value.

Chinese signs (Photo by Tian Hua)

The survival dilemma of Chinese 困

China is very precious, but facing the danger of extinction, which is very sorry. So, "Giant Panda in the Water" -How is the survival of Chinese maggots?

To understand Chinese 鲟, we must first understand its unique habits. Chinese 洄 is a traveled fish, that is, growing off the sea and breeding in the Yangtze River. They usually grow and develop in the sea. When the male fish grows to the age of 9 to 18 and the females reach the age of 14 to 26, they start to swim to the Yangtze River to the Yangtze River. Breeding offspring.

In the summer and autumn seasons of each year, the Chinese crickets living in the sea of ​​offshore will go upside down along the Yangtze River mouth. After more than 3,000 kilometers of tracers, they will go back to the upper reaches of the rivers. spawning. After spawning, the parent (refers to the development of a male or female with breeding ability, also known as the breeding, also known as planting fish). It goes back to the sea. The cubs grow to about 15 cm and will also swim back to the sea. Every time they lay their eggs, they return to their hometown, and they are extended by the ancients as the meaning of not forgetting their hometown, looking for roots and asking their ancestors, so they are called "Chinese".

Once, 800 kilometers from the lower reaches of the Jinsha River to the upper reaches of the Yangtze River, there were more than 16 Chinese spawning venues found in China. The size is huge and cannot be turned over the dam. The stubborn Chinese 大 did not sit still because the dam was blocked, but quickly found a new spawning field. The location was 4 kilometers below the Gezhou dam dam. Later, the normal operation of a new large -scale water conservancy project also allowed the only spawning field for China to face new problems, including changes in water levels in autumn and winter, rising water temperature, delayed egg temperature, etc. The hardness of plug and river beds is also affected. The number of Chinese spawning fields not only decreases from to one to one, but the length of the spawning field has also been reduced from hundreds of kilometers to four kilometers, and its living environment has undergone tremendous changes.

The comprehensive assessment report of the 2013 Chinese Academy of Engineering shows that before the "Yangtze River No. 1 Dam" -before Gezhou Dam is cut off, more than 3,500 tails in the Chinese crickets in the Jinsha River in the upper reaches of the Yangtze River each year. 500 tails, in 2010 to less than 100 tails, only 57 tails were found. It was also included in the "Extreme Endangered" (CR) level by the Chinese Nature Conservation Alliance (IUCN) this year. The number of estimates in 2019 is 16 tails, 13 tails in 2020, and 15 tails in 2021. It has not been discovered for many years. It has not discovered its natural reproduction. Even since 2017, it has been interrupted for five consecutive years and natural reproduction.

Protect Chinese 行, act!

The protection of the continuation of the Chinese species began in the 1980s. The sexual maturity cycle of Chinese crickets is long. Generally, the males will take 9 years to mature, and the female will take 14 years to mature, and the protection is very difficult.

As early as 1982, my country began the artificial reproduction work of Chinese magpies. In 1983, it was successful. After forty years of unremitting efforts, scientific researchers successfully breed the first generation, second generation, and son 2.5 generations. The seedlings continue to flow to the Yangtze River, which effectively supplements the number of natural populations to a certain extent. In recent years, the results of Sonna investigation and evaluation showed that the highest percentage of the release of China ’s pupa has exceeded 70%. For a long time, artificial breeding of Chinese crickets has two methods: pond flowing and circulating water breeding.

Most catfish belong to cold water -based fish, and Chinese crickets are no exception. However, the flowing pond cannot effectively regulate breeding water temperature in the high temperature season. As a result, the Chinese cricket -pro -fish gonad development is abnormal. It is difficult to obtain high -quality eggs and sperm at the best time point.

The second generation of the son of the son of Chinese 精 Collection sperm (photographed by Tian Hua)

Researchers from the Institute of Water Engineering Ecology of the Chinese Academy of Sciences of the Ministry of Water Resources collected and sorted out the water temperature data of the Yangtze River and the coastal continental shelf. Compared with the artificial domestication and breeding water temperature requirements of other catfish, they finally found the key password of '25 ℃'.

With no higher than "25 ° C" water temperature as the control point, and the principle of regulation of the annual water temperature, the normal development of Chinese gonads in the light -water breeding environment of human workers can be smoothly induced.

In the Laboratory Library of the Three Gorges of the Three Gorges of the Institute of Water Engineering Ecology, there are two sets of large circular aquaculture systems designed to cultivate Chinese crickets. The water quality and water temperature regulation capacity meets the needs of water environmental factors for the development of Chinese tadpoles.

In October 2021, the first generation and the second -generation Chinese sanctuary of the Institute of Water Engineering Ecology produced high -quality eggs and sperm. The fertilization rate reached 77.9%and the incubation rate reached 89.5%. The best level of Chinese has been working since the work of all artificial reproduction.

Artificially breeding Chinese embryo (photographed by Tianhua)

Chinese bleeding embryo in the film (Photo by Tian Hua)

In the end, there were 110,000 tails of the 2.5 generations of Chinese raccoons in the 2.5 generation of the seeds, and about 60,000 juveniles were cultivated. At present, the batch of juveniles is 30-50 cm in length and a maximum weight of 1,000 grams.

Artificial cultivation child 2.5 generation of Chinese seedlings (Tianhua)

Team of "Obstetrics" experts in China also carried out another breeding experiment: using the second -generation male fish frozen essence of Chinese tweezers in 2020, and the fertilized fertilization rate collected this time, the fertilization rate reached 26.5%, and the incubation rate exceeded 80 %.

Since then, the development of Chinese and male and female gonades is not synchronized, and no longer plagued scientific research reproduction. Using this ultra -low -temperature preservation technology, China ’s entire artificial breeding has more 'window time', which has also greatly improved the genetic diversity of artificial breeding of Chinese crickets.

On March 28, 2022 (China Capricorn Protection Day), 50,000 artificially reproduced "Zi 2.5 Generation" Chinese catfish fry the Yangtze River in Wuhan section. This is the largest stream of Chinese launching activities in the Wuhan section of the Yangtze River so far, laying a solid foundation for effectively promoting the natural reproduction and recovery of Chinese crickets.

Chinese 鱼 Flow Flowing Fish

Although scientific researchers have made some progress in the protection of Chinese crickets, the conservation work of Chinese crickets is still long -term. Researchers still need a healthy water ecological environment to maintain the Chinese magpies while hard work and breeding techniques. Breeding and survival venues.

In order to "giant pandas in the water" -Choneya no longer becomes the silhouette of history, and please start with me to protect the beautiful Yangtze River and ocean, and let them swim on the territory of Greater China.

Produced: Popular Science China

Author: Zhang Yuanyuan Tianhua (Institute of Water Engineering Ecology, Chinese Academy of Sciences) of the Ministry of Water Resources)

Producer: China Science Popularization Expo

Edit: Wang Tingting

The China Science Popularization Expo is the Science Popular Science Platform of the Chinese Academy of Sciences. It is sponsored by the Computer Network Information Center of the Chinese Academy of Sciences. Relying on the high -end scientific resources of the Chinese Academy of Sciences, it is committed to spreading cutting -edge scientific knowledge and providing fun science and education services.

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