I. Answer the question

According to the picture provided, This is an organism of the genus Macrocephalus of the family Cyprinidae, Chinese name: Macrocephalus

II. Names and categories

The Macrocephalus (scientific name: Opsariichthys bidens) is a fish of the family Carpidae, genus Macrocephalus. The body of the horse mouth fish is long and laterally compressed. The abdomen is rounded. The snout is long. The posterior end of the lower collar extends to the anterior margin of the eye, which is convex at the anterior end and has a depression on each side. Eyes equal in size. Lateral line complete. Body grayish black dorsally, silvery-white ventrally, with light blue vertical stripes on the sides of the body, and pectoral, ventral and anal fins orange-yellow.?

III. Morphological Characteristics

1. The length of the horse mussel is 3.2-5.0 times the height of the body, 3.2-4.0 times the length of the head, 5.0-7.5 times the length of the caudal peduncle, and 8.7 -12.0 times. Head length 2.6-3.5 times snout length, 4.6-7.3 times eye diameter, 2.7-3.7 times eye spacing. Caudal peduncle 1.3-1.9 times as long as height of caudal peduncle.

2. The body of the horse mouthed fish is long and laterally flattened, the height of the body is slightly less than or equal to the length of the head, and the abdomen is rounded. The muzzle is blunt. The mouth is subsuperior, with a downward-sloping cleft, and the maxilla extends backward up to the middle of the eye vertically below. Mandible slightly longer than maxilla, with a prominent anterior protuberance coinciding with the central maxillary depression, and the lateral margins of the upper and lower jaws concave and convex. No mouth whiskers. Males with well-developed beadstar on muzzle and buccal region. Eyes small, laterally superior. Postocular head length longer than muzzle length. Eye spacing about equal to or slightly less than muzzle length. Body covered with rounded scales, medium-sized, sparseness of scales slightly variable from south to north. Lateral line complete, markedly recurved above pectoral fins, extending posteriorly along lower part of body, returning to middle of body after entering caudal peduncle.?

3. The start of the dorsal fin of the horse mussel is approximately opposite or slightly anterior to the start of the ventral fin, and slightly farther from the end of the muzzle than from the base of the caudal fin. The pectoral fins are slightly pointed at their ends and do not reach the beginning of the ventral fin backward. The ventral fins are blunt and do not end as far as the anus. The anus is immediately before the anal fin. The anal fin is long, and in sexually mature individuals the longest fin extends backward to the base of the caudal fin. The caudal fin is forked and pointed at the end, with a slightly longer lower lobe.?

4. The hypopharyngeal bones of the horse mussel are curved and narrow. The pharyngeal teeth are conical with hooked ends. Gill rakers are sparse. Intestinal tube length about equal to body length. Swimbladder 2-chambered, posterior chamber about twice as long as anterior chamber, end slightly pointed. Peritoneum grayish white, occasionally with tiny black spots.?

5. Dorsum gray-black when living, abdomen silvery white. Cheeks and even and caudal fins lower lobe orange-yellow, dorsal fin membrane with black spots, the body side with 10-14 light blue vertical stripes. Males are especially brightly colored during the reproductive season. Fixed specimens with blue spots darkened. Females have inconspicuous transverse spots, with only one inconspicuous longitudinal black stripe on the caudal side of the body.

Four, habits

1. Habitat

The horse mouthed fish is a stream small predatory ferocious fish, inhabiting the upper layer of the city of the water, usually group activities, in the wild, like to live in the shallows of the rapid flow of water. In the wild, it likes to live in the shallows of fast-flowing water. It can live in small streams or tributaries of rivers whose substrates are sandy and gravelly; it can also live in still-water lakes, reservoirs and ponds, and is rarely seen in deep water of rivers.

2. Food

The horse mouthed fish to small fish, shrimp and a variety of aquatic animals for food, the general body length of 2.0-3.5 centimeters of juvenile fish mainly ingesting crustaceans and aquatic insects, but zooplankton such as branchiostomatids accounted for a considerable proportion of the body length of 10.0 centimeters of horse mouthed fish has been able to completely devour the juvenile fish of other fishes, strong feeding power, rapid growth, the first year of growth, the first year of growth, the first year of growth, the first year of growth, the first year of growth, the first year of growth, the first year of growth, the first year of growth. The growth is rapid, the 1st year of growth is more rapid, up to 7-11 centimeters. The structural characteristics of the predatory organs and digestive system of the horse mouthed fish are closely related to its carnivorous nature, and its digestive tract consists of the oropharyngeal cavity, esophagus and intestines, with no stomach, no maxillary teeth, pharyngeal teeth, and the intestinal tract is simply coiled and divided into the anterior, middle, and posterior intestinal tracts, and the average value of the intestinal index is 1.04±0.15.

Five Distribution Ranges

Morse mouthed fish are distributed from the Liaohe River to the Liangguang River, and the distribution is as follows It is found from Liaohe River to Liangguang. In the Yellow River Basin it is found only in Tianshui, Gansu; Wolongsi, Zhouzhi, Xianyang, Weinan, Huayin and Tongguan, Baoji, Shaanxi; Xin Jiang, Yuxiang, Yongji, Shanxi to Lingbao, Luoyang, Gongyi City, Kaifeng, Henan Province and Dongpinghu, Jinan, Lijin and Kenli, Shandong Province. And beyond China to Japan, Korea and Vietnam.

Sixth, reproduction

Maqui reached sexual maturity at the age of 1 winter fish, and has the ability to reproduce, for the type of spawning many times a year, the breeding season for the March-August, in South China, East China and Central China breeding period in general in March -The breeding season is from March to August, and in South, East and Central China the breeding period is generally from March to June, while in Northeast China the breeding period is mostly concentrated in June to August. Although the fish is heteromorphic, it is not easy to distinguish between males and females at the juvenile stage, but during the breeding season, the sexually mature males of the fish have obvious secondary characteristics, with bright "marriage color" on the body surface, and the upper and lower jaw cheeks, pectoral fins and anal fins are covered with granular chasing stars. Individual fecundity varies considerably in different regions, with an average absolute fecundity of 5000-8000 grains/tail and an average relative fecundity of 44-207 grains/g body mass, and is related to the size and age of the sexually mature individuals. It may also be related to the geographic latitude, the higher the latitude the lower the relative fecundity of body mass.

Seven, the main value

1.Nutritional value

Maia fish belongs to the high-protein, low-fat fish, the muscle crude protein content of 16.71% -18.78%, crude fat content of 16.71% -18.78%. 18.78%, crude fat content of 1.36%-2.71%, crude ash content of 1.22%-1.36%, moisture content of 76.81%-79.67%, amino acid content of 16.23%-21.28%. The total essential amino acid content is 5.51%-8.76%, saturated fatty acid content is 19.2%-29.31%, monounsaturated fatty acid content is 15.57%-36.42%, and polyunsaturated fatty acid content is 32.21%-44.45%. 44.45%. There were some differences in the nutrient composition of horse mackerel muscle in different regions and farming methods, and the nutrient composition of male horse mackerel muscle was slightly higher than that of female, and the amino acid index of wild horse mackerel muscle was higher than that of artificially bred horse mackerel muscle.

2. Economic value

With people's concept of renewal and environmental protection awareness, and horse mackerel artificial breeding and breeding technology has been a breakthrough, artificial breeding of the required fry can be produced on a large scale, horse mackerel has become a new species of aquaculture, the market prospect is broad. Horse mussel is one of the Chinese brook trout series species with the characteristics of rapid growth, high yield, wide distribution, strong reproduction, and the ability to reproduce at the age of 1+. It can be cultured not only in net boxes but also in ponds, which is very suitable for the development of aquaculture in mountainous areas. The artificial culture of horse mussel has been carried out in many places in China, such as Zhejiang, Hunan, Hubei, Liaoning, etc. Various modes of commercial fish culture, such as net box in reservoirs, river water ponds, and circulating facilities in ponds, have been successfully carried out, and it has become a new fishery specialty industry. For example, in Xinchang County, Shaoxing City, Zhejiang Province, where mackerel has become a new specialty industry, the Rongxin Aquaculture Professional Cooperative promoted more than 3 million mackerel commercial fish farming in 2015, with a production of more than 50 tons, and implemented a mackerel seed stocking and releasing 300,000 mackerel. The industrialized development of horse mouthed fish culture has become one of the important industries to help rural revitalization. Particularly suitable for the promotion of aquaculture in poor mountainous areas, its low cost of farming, high efficiency, precision poverty alleviation in mountainous areas has certain species advantages, in promoting the optimization of aquaculture species structure in mountainous waters, to increase the quality of aquatic products and improve the economic benefits of aquaculture plays an important role, is to achieve poverty alleviation of a way to become rich.