#Animals##野生动物保护 #
Protect nature, protect life, protect endangered animals, and light up the world! Thank you all for taking the time to read my article and learn more about endangered animals. Welcome to leave a message in the comment area to discuss.
The Yangtze River, the mother river of the Chinese nation, is rich in biodiversity. In this sparkling water, there lives a mysterious and rare aquatic mammal - the Yangtze finless porpoise. They are treasures in the ecosystem of the Yangtze River, witnessing the magic of nature and the tenacity of life.
Neophocaena asiaeorientalis (scientific name: Neophocaena asiaeorientalis), also known as narrow-ridged finless porpoise, Yangtze finless porpoise, black porpoise or river pig. Along with the East Asian finless porpoise, they were once considered one of the two subspecies of the narrow-spined finless porpoise. It was not recognized as an independent species until 2018. This increased the number of cetacean species from 89 to 90. This also marks the addition of a new endemic species to China.
Yangtze finless porpoise: cute "smiling angel"
Yangtze finless porpoises are small, they are 1.4-1.7 meters long and weigh generally about 70 kilograms, and the largest can reach 220 kilograms. The head is short and rounded , without a beak , and the forehead is slightly protruding forward. The body is spindle-shaped, with no dorsal fin on the dorsal spine, only a 3-4 cm skin bump corresponding to the dorsal fin. The flippers are broad, slightly triangular; The caudal fin is broad and the posterior margin is concave and crescent-shaped. The whole body is blue-gray or tile-gray, the abdomen is light in color, the lips and throat are yellow-gray, and there are some irregularly shaped gray spots on the abdomen. Some individuals have a pale color between the base of the ventral two flippers and between the anus, or a reddish color, especially during the breeding period.
The Yangtze finless porpoise is a unique freshwater dolphin with an elegant body shape and smooth skin. They are particularly noticeable in the water. Although finless porpoises have small eyes, they have extremely sensitive hearing and echolocation capabilities, and can quickly catch the movements of prey underwater.
The Yangtze finless porpoise has a lively temperament, often jumping up and down in the water, and its body is constantly rolling, jumping, nodding, spraying water, sudden turning and other movements. When swimming sideways, one leaf of the tail fin emerges from the water, swaying from side to side, and streaks through the air. After being frightened, he swims rapidly, and then takes his body into the air at one time or several times in a row, most of which is exposed to the surface, only the tail leaf slides forward in the water, and occasionally the whole body jumps out of the water, reaching a height of 0.5 meters. When swimming upright, two-thirds of the body is exposed to the surface of the water, and the posture is perpendicular to the surface of the water for several seconds. Whenever there are large boats sailing in the river, finless porpoises like to follow closely behind them or ride the waves.
It also has an interesting spitting behavior, exposing its head to the surface of the water, swimming forward quickly, closing its mouth one by one, and squirting water from its mouth from time to time, sometimes squirting water 60-70 cm away. When breathing, only the head is exposed, the tail fin is hidden under the water, and then dives underwater in a bouncing shape. The breathing interval is generally about 1 minute, but if frightened, the dive time can be up to 8-9 minutes. Generally, if you do not bow your waist when entering the water, you will not stay underwater for a long time, but when you dive with a large range of bow waist, it means that you will dive deep and will not be out of the water continuously. When swimming downstream, the position of the next outlet is generally about 10 meters before the previous outflow, and the position of the previous outlet is generally about 5 meters before the previous outflow position, and the countercurrent can only advance about 3 meters.
If a windy weather is imminent, the porpoise's breathing rate will increase, the surface of the water will be high, and the head will mostly "blow the wind" out of the water in the direction of the wind, which fishermen working on the Yangtze River call "worshiping the wind". This may be due to the lower air pressure before the weather change, forcing it to increase its breathing rate to get enough oxygen.
In the waters or tributary estuaries of the brackish and fresh water of the Yangtze River, the confluence of the lake estuary and the Yangtze River, the relatively slow flow speed of the Jiangwan estuary, the places with more fish are ideal habitats for finless porpoise activities, and often integrate large groups during the fish flood season, which can live in seawater, brackish water or fresh water. The finless porpoise feeds on fish, shrimp and cephalopods, and tends to migrate with migratory fish. Every spring, it enters the Yangtze River in order to hunt for large silverfish, knife fish and mackerel at the mouth of the Yangtze River. There is also large-scale, long-distance migration of the Yangtze finless porpoise population.
Generally speaking, whitebait is marketed as finless porpoise, and there are many finless porpoises in whitebait. Generally, the probability of not forming large flocks, small groups of 2-3 more active animals, and 1-5 heads swimming together is 88%, and only groups of dozens of animals can be seen during the breeding period.
The "neighbors" of the Yangtze finless porpoise
The Yangtze finless porpoise lives in the same waters as the white-tip dolphin, and they are both cetaceans. However, their habitats do not coincide. White-tip dolphins live in the upper reaches of the Yangtze River, while Yangtze finless porpoises live in the middle and lower reaches of the Yangtze River. The difference between the two is that the white-sided dolphin lives twice as much as the Yangtze finless porpoise because it has more contact with the natural habitat of the Yangtze River basin. The white-sided dolphin is also a mammal, it is endemic to China, but it is not related to the finless porpoise. At present, both the Yangtze finless porpoise and the white-tip dolphin live in fresh water, but the possibility of the Yangtze finless porpoise and the white-tip dolphin living in the same water area is also very small. Therefore, if the two species are in the same waters, then there is a chance that they will conflict. So, they are called "neighbors".
The population of the Yangtze finless porpoise is already in jeopardy
In 1982-1983, a total of 352 finless porpoises were found in the lower reaches of the Yangtze River, and it is estimated that there are about 1,000 finless porpoises.
According to the survey in June 1991, it was estimated that there were 394 head in the section from Yichang to Wuhan, 104 head in Dongting Lake, 1,652 head in the section from Wuhan to Jiangyin, 52 head in Poyang Lake, and about 500 head in the section from Jiangyin to Wuyin, a total of about 2,700 head.
The fact that finless porpoises are widely distributed along such a vast Chinese coast, and the number of finless porpoises hunted each year is estimated to have been in the tens of thousands. According to the survey, the number of coastal finless porpoises has shown a sharp decline compared with the 50s or 80s.
According to information released by China's Ministry of Agriculture and Rural Affairs in July 2018, there are only about 1,012 left, including about 445 in the main stream of the Yangtze River, about 110 in Dongting Lake and about 457 in Poyang Lake.
At the current rate of decline (13.7% per year), experts warn that the Yangtze porpoise is likely to become extinct around 2025.
The Yangtze finless porpoise is the main victim of passive fishing gear overcatch in the waters off the mainland coast, mainly because the amount of fixed fishing gear such as inserting nets is relatively large. At the same time, the construction of locks and dams along the river has blocked the passage of migratory fish to spawning grounds, and overfishing has exacerbated the decline of fishery resources, reducing the food of the Yangtze finless porpoise and posing a threat to the finless porpoise.
In order to protect the Yangtze finless porpoise, in 1979 the State Council promulgated the Regulations on the Protection of Aquatic Resources, and Article 2 of the regulations stipulates that the finless porpoise will be given priority protection. At present, the Yangtze finless porpoise is listed as a first-class national key protected animal, and the IUCN Red List of Threatened Species lists it as critically endangered (CR).
The protection of the Yangtze finless porpoise is inseparable from the joint efforts of people. The government, scientific research institutions, civil society organizations and the general public should actively participate in the action of protecting the finless porpoise. Through strengthening environmental protection, strict fishing management, and carrying out scientific popularization, we will create a safer and more livable living environment for finless porpoises.