Artificial culture of Chinese alligator

In 2003, a one-year special study was conducted in Anhui alligator nature reserve. During the monitoring period, the date, time, times and weather conditions of the roar were recorded. The Chinese alligator begins to roar in March and stops roaring in June every year. 165438+ 10. The howling times of Chinese alligator vary significantly in different months, and June is the most frequent, accounting for 26.0% of the whole year. During the breeding period (June-September), the howling times of Chinese alligator are significantly higher than those in the non-breeding period, and there are significant differences at different times of the day. 0.05), the weather change has no effect on the roar. The analysis shows that the roar of Chinese alligator is closely related to its reproductive behavior. The main purpose of yelling is to attract the opposite sex and also to protect the field.

On April 27th, 2003, two healthy adult Chinese alligators, one female and one male, were released to the Red Star Chinese alligator reserve in Xuancheng, Anhui Province. Their active areas were measured by radio telemetry four weeks before release, and 372 loci were recorded. Their activities are also observed by telescopes during the day and by light counting at night. The results showed that after 3- 14d, the three Chinese alligators were in different stable regions and had domain characteristics. The activity area of men is larger than that of women, and the change of daily activity area is larger than that of women. The local environment tends to be close to the coast with dense vegetation.

According to 150 Chinese alligator embryos with different gestational ages, the embryonic development process of Chinese alligator was divided into 30 stages. Early embryos are mainly based on external morphology, such as somites, body bends, brain vesicles, sensory organs, appendages, branchial arches, facial processes, heart and skin. Late embryos are mainly based on histological indexes of organ development. The results showed that in the first 20 stages, the gestational age of each stage was very consistent with that of Mihe crocodile, while in the last 8 stages, the gestational age was different from that of Mihe crocodile. According to the analysis, the histological index of organ development should be added to the staging basis of late crocodile embryos, so that the embryo development of different crocodiles has the same staging standard, which provides basic data for the follow-up study of crocodile developmental biology. 1979 A Chinese alligator farm was established in Xiajiadu, Xuanzhou, and artificial feeding was studied. 1982 to establish the Chinese alligator reserve, 1983 to establish the Chinese alligator breeding research center in the reserve, with an investment of170,000 yuan to build 8 small-scale breeding ponds with an annual breeding pond of 65,438+. After several years of experiments, it was basically successful, the survival rate of artificial incubation reached 95.4%, and more than 20 thousand young crocodiles were bred, which won the national natural science award.

It is difficult for Chinese alligators to breed under artificial feeding conditions. 1980, the first young crocodile was bred in China, which became a precedent for successful breeding under artificial breeding conditions. The alligator provincial nature reserve in Changxing County, Zhejiang Province is a diversified comprehensive nature reserve base integrating ecology, scientific research and education.

Since the establishment of the nature reserve, the population of Chinese alligator has greatly increased through the combination of in-situ protection and artificial reproduction, which has initially lifted the danger of extinction of this species. Many conservation work began in the 1970s. 1979 Anhui Xuancheng alligator breeding research center was established, 1980 alligator nature reserve was established. At the same time, the people of China have also carried out a series of conservation actions, increasing the number of Chinese alligators. 1983 census found that there were only 500 wild Chinese alligators. 1992 census found that the number of wild Chinese alligators increased to 900. The Chinese alligator breeding research center has made great achievements. In recent years, 7,000 young crocodiles have been hatched, which is very gratifying. The great success of artificial breeding has created conditions for the recovery of the number of Chinese alligators.

The protection measures for Chinese alligator in China are mainly legal protection and artificial captivity. Anhui Provincial Forestry Department successfully implemented the captive project. The Anhui Alligator Breeding Research Center in Xuancheng has artificially raised more than 5,000 crocodiles.

The physiological characteristics of Chinese alligator make it resistant to long-distance transportation. There is no need to take special measures, throw bait or change water during transportation, and water it properly when the weather is hot. It can be transported in wooden cases with breathable barbed wire installed on one side. Chinese alligators like to live alone. Under the condition of artificial breeding, the density should be appropriate, generally about 50 ponds per mu. If it is a young crocodile, the stocking quantity can be increased; If it is a parent crocodile for breeding, the density should be reduced. Over-stocking will lead to fighting injuries to crocodiles; If the stocking is too thin, the water body can't be used effectively. Generally, after stocking, Chinese alligators will appear restless and swim around in unfamiliar environment, especially at night, eating less and lurking underwater when there is a slight movement. It takes about 1 week to adapt to the new environment.

The daily management of artificial feeding of Chinese alligator mainly includes feeding, patrol, disease prevention and capture measurement. The Chinese alligator has low requirements on bait and wide feeding habits, and can feed fish, meat and animal viscera. You can also raise some snails, mussels and fish in the pond, which can not only use the water body, but also reduce the amount of bait. Try not to feed rotten bait and avoid a single variety. At the beginning of feeding, Chinese alligators were not used to coming to the food table, preferring to feed at night. They can feed food at the food table at night and then gradually walk to the food table. Check the eating situation the next morning, mainly to see if there is any surplus, and make records.

Chinese alligators eat food from May to September, and it is most vigorous from June to August, accounting for more than 80% of the annual food intake. The daily feeding amount should be strictly controlled, and the feed accounts for 1% of the body weight, that is, it grows well. If overfeeded, it will make it obese, accumulate a lot of fat in the body, and die easily, or die in a wintering cave. Because fat blocks oppress the gonads in the body, they can't develop normally at the same time, which leads to the decline of reproductive capacity. Obese Chinese alligators will have uncoordinated mating behavior and cannot hug and mate normally. The growth rate of alligator sinensis was relatively fast in the early stage, especially before the age of 4, and its body length and weight increased greatly, and then gradually slowed down. The growth characteristics of Chinese alligator are as follows: 0-4 years old, the body length and weight increase greatly; After the 4th instar, the body length and weight increase slowly, but the weight growth ratio is higher than the body length growth ratio. There are usually the following kinds of cases in which cultured Chinese alligators die due to pathological changes: most of the cases of fullness occur under the conditions of excellent breeding conditions and good bait environment. Anatomy shows that a large number of fat blocks are accumulated in the body cavity, and the liver, pancreas, intestine and stomach are compressed. Death caused by rotten skin infection can lead to trauma. For example, after biting and smashing, the wound purulent gradually expanded, and finally died without treatment. When the cold wave suddenly comes or the cave collapses, the crocodile can't find the cave and overwinters outdoors, unable to resist the cold and dies. Death due to systemic diseases in the body, and death due to pathological changes in some organs of various systems such as digestion and respiration. In the process of artificial breeding, "eye disease" will also be found, that is, crocodiles are afraid of entering the water, and their eyes secrete more viscous liquid, and then swell, which is generally not life-threatening, and can be cured with chloramphenicol ointment. In the management of artificial feeding, if you find that you stop eating, move slowly, don't move your head, your abdomen is swollen, and your mouth is congested, you may have lesions, so you should isolate and treat them as soon as possible. To prevent diseases, it is necessary to keep the environment clean, often disinfect the pool water, feed antibacterial drugs and bait, and have stronger disease resistance.

Chinese alligators should be sampled and measured in each growing season. If the number of farmed alligators decreases, you can check the number separately. A large number of aquaculture, according to the Tangkou sampling measurement. Because of its sharp teeth, bites often occur when catching, so be more careful. You can put a long pocket-shaped fishing bag on its head, press it on the ground to measure its body length, and then put it in the bag to weigh it. In daily farming, scales in different directions can be marked on the dining table, and when crocodiles climb to the dining table for food, their lengths can be roughly measured. This method is suitable for ponds with a large number of aquaculture and neat specifications. According to the 2008 China State of the Environment Bulletin, the work of releasing endangered species such as Chinese alligator into nature has been progressing steadily. The species of Chinese alligators have been effectively protected and the number has generally increased. The total number of Chinese alligators in China has reached 10000.

Since June 2003, Anhui alligator National Nature Reserve Administration officially began to release alligators into the wild. Six wild releases allowed 36 Chinese alligators to return to nature, including 33 in Gaojingmiao Forest Farm in Langxi County, Xuancheng.

In fact, releasing wild animals is not that simple and requires a lot of preparation. Wang Chaolin said that not all artificially bred Chinese alligators can be released into the wild. "First of all, we need to choose a young and strong Chinese alligator. After the veterinary examination is qualified, we will take blood samples for DNA testing to prevent close relatives from pairing. Then, we will inject an electronic chip into each Chinese alligator as its lifelong ID card. The Chinese alligator, which has been selected at different levels, will be put into the wild domestication base for wild domestication to improve its wild viability. " Wang Chaolin said that after about a year of domestication in the wild, the staff would catch these Chinese alligators, put them on radio transmitters, and then put them into wild release sites. After being released in the wild, the School of Life Sciences of Anhui Normal University will patrol and monitor them, and learn about their survival in the wild by receiving the signals from wireless transmitters. "From the first release in the wild in 2003, so far, we have not found a Chinese alligator dead, and they are all laying eggs, which shows that we have achieved initial success." Wang Chaolin said happily.

Wang Honggen, the stationmaster of Langxi County Protection Station, said that in 2008, the forest farm set aside 52 mu of land, established a field area in full accordance with the habits of Chinese alligators, and put 2 15 Chinese alligators into a pond, and has laid eggs 15 so far. Since 2009, a new wild area has been built, which is also 8 ponds. 20 10 June, 240 Chinese alligators were put into nature reserves for wild protection.

In 2008, Chinese alligators released in the wild laid eggs for the first time, 19. So, does this mean that the release in the wild is really successful? In this regard, Wang Chaolin said that this can only be regarded as a preliminary success. "There is a certain standard for success, that is, the released Chinese alligator not only adapts to the wild environment, but also can settle down and lay eggs, and the offspring can grow up and reproduce again. When the grandson of the first Chinese alligator was born, we can say that the Chinese alligator was really released successfully. Because it takes 7 years for the male Chinese alligator to grow up and 9 years for the female, we won't know the final result until 20 15 at the earliest. "