Acipenser sinensis is a precious animal living in China and one of the key protected animals in China. Because they belong to bony fish, they are a kind of bony fish and naturally belong to fish. From the specific classification, Chinese sturgeon belongs to sturgeon, which itself contains many varieties, and Chinese sturgeon can be said to be a very precious one.
The difference between Chinese sturgeon and sturgeon
I. Appearance characteristics
Chinese sturgeon: Chinese sturgeon is long, with tapering ends, narrow back and straight abdomen. The head is in the shape of the Yangtze River Delta. The tip of the kiss is long. The nose is big and both nostrils are in front of the eyes. The water spray hole is cracked. The eyes are small and oval, located in the back half of the head. There is a wide gap between the eyes. The mouth is low, transverse, protruding and elastic.
Lip hypoplasia with tiny nipples. There are two pairs of whiskers in the center of the muzzle, which are arranged in an arch shape. The length from the fibrous root to the front edge of the muzzle is shorter than 1/2, and the outer side must not reach the corner of the mouth. The branchial fissure is large and the pseudobranchial is developed. Gill harrow is sparse and short and thick. 1 dorsal fin, posterior position, concave posterior edge, starting point in front of gluteal fin. The gluteal fin is opposite to the dorsal fin, below the middle of the dorsal fin.
The ventral fin is small and rectangular, located in the lower part of the center of the body, close to the gluteal fin. The pectoral fin is well developed, oval and low. The caudal fin is curved, the upper leaf is particularly developed, and there are 1 longitudinal spiny scales on the upper edge of the caudal fin.
Sturgeon: Sturgeon is a rare ancient fish left over from Mesozoic10.5 billion years ago. Between cartilage and hard bone, the degree of ossification of bone generally decreases. The central axis is an ossified elastic notochord without a vertebral body. Most of the cartilaginous shells along the skull are not ossified. The caudal fin is curved, the base of the lateral fin is broad, and the dorsal fin is opposite to the gluteal fin.
The ventral fin is located in front of the dorsal fin, with spiny scales at the base of the fin and caudal fin, spiral valves in the intestine, anus and drainage holes close to the base of the ventral fin, and the opening of fallopian tube far from the ovary.
Second, living habits.
ACIPENSER sinensis: ACIPENSER sinensis is the largest and longest-lived freshwater fish, with a strong body, huge individuals and a long life span, with the longest life span reaching 40 years. After the Chinese sturgeon enters the river, it must stay in the river for one year and arrive at the spawning ground in June 5438+the following year 10.
During this year, the Chinese sturgeon does not always swim upstream, but sometimes swims and stops, and sometimes lurks in the potholes in the river for several days. In the autumn of the following year, it can be traced back to the fast-flowing upper reaches of the river with gravel at the bottom, and the breeding population gathered in the spawning ground to breed.
Acipenser sinensis is a kind of benthic fish, which belongs to omnivorous fish with animal food as the main food. It mainly feeds on some small or slow-moving benthos, including shrimp, crab, fish, mollusks and aquatic insects.
Because of the different kinds of food in the living environment, the young fish mainly feed on chironomid larvae, dragonfly larvae, mayfly larvae and plant debris in the middle and upper reaches of the Yangtze River, while the young fish in the salty and fresh water area of the estuary feed on shrimp, crab and small fish. Parent fish don't eat during migration.
In the offshore waters outside the Yangtze River estuary, the feeding intensity of ACIPENSER sinensis increased, generally at level 3-4. The food is mainly fish and crabs, as well as shrimp and cephalopods.
Sturgeon: Sturgeon is a kind of benthic fish with a very narrow feeding habit and belongs to carnivorous fish. In rivers, it mainly feeds on some small or slow-moving benthos, and in the ocean, it mainly feeds on fish, followed by crustaceans and molluscs.
Third, the distribution range.
Chinese sturgeon: Chinese sturgeon is the only sturgeon that crosses the Tropic of Cancer. It used to be mainly distributed in coastal areas and major rivers south of the west coast of the Korean Peninsula, from Jinsha River to the mouth of the Yangtze River in China. Other water systems, such as Ganjiang River, Xiangjiang River, Minjiang River, Qiantang River and Pearl River, occasionally appear, with the Yangtze River producing more.
Sturgeon: At present, sturgeons in China are mainly distributed from Jinsha River to the mouth of the Yangtze River, and other water systems such as Ganjiang River, Xiangjiang River, Minjiang River, Qiantang River and Pearl River occasionally appear. Abroad, it is found in the mouth of Han River in South Korea, Lijiang and the west side of Kyushu in Japan.