(I) Morphological characteristics Barracuda (mugil soiuy), also known as meat stick (Liaoning, Hebei), red-eye fish (Shandong), red-eye fish, red-eye (Zhejiang, Fujian), vegetarian fish (Guangdong), etc. Cylindrical body, gradually flattened back, head short and wide, eyes smaller, fat eyelids underdeveloped. Eyes are red and yellow. The base of the pectoral fins is free of scales. The caudal fins are slightly concave on the trailing edge. The back is grayish-gray with light gray on both sides, light gray on both sides, ventral white, and black stripes on the scales on the side of the body.
(b) Distribution The carps are very widely distributed, and almost all of them can be found in the world. However, tropical and sub-tropical waters are the most abundant species. They are not only species but also large in quantity. It is the most widely distributed in the temperate, tropical and subtropical coastal waters. It is distributed in all sea areas and coastal estuaries in the five major European, Asian, U.S., U.S., and U.S. states, and has become one of the most widely distributed fish species in the world. Important economic fishes in the Atlantic, Pacific, Indian Ocean, Mediterranean and Black Sea. Polygonidae are distributed in the coastal areas of China, from Hainan Island in the south, to Lushun and Dandong in the north, and the number of brackish and freshwater domains with lower salinity in Inner Bay is more. The general trend of distribution is that there are fewer species in the north and more species in the south, and the South China Sea and Taiwan, in particular, have the most species and yields are most abundant. The most common carp and barracuda are widely distributed in the South China Sea, the East China Sea and the Yellow Sea. The squid is more in the south and has a certain amount in the coastal areas of Shandong. The barracuda is more in the north and the Bohai Bay and the Yellow Sea are more dense along the coast.
Second, the ecological habits (a) of the adaptation of the environment Barracuda tropical shallow sea, middle-level fish, hi living in coastal nearshore, estuaries, bays and other salty waters, but also with the tide into freshwater. Barracuda adapts to a wide range of salinity and can live in seawater, brackish water and pure water. Barracuda can live from 38 inches of salt water to pure fresh water. Based on the salt and salinity of barracuda, in addition to breeding in seawater and brackish water, it is also possible to eat oysters. (7) Bald and small? SPAN lang=EN-US> Barracuda is a warm-water fish, but the temperature of water The scope of application is also relatively wide. Barracudas can live in the water at 1-30°C. The optimum water temperature is 12-25°C and the lethal low temperature is -0.7°C. Barracuda has a strong ability to adapt to changes in water temperature. For example, in the artificial breeding of barracuda, the water temperature gradually increased from 15.8°C to 30.2°C in 30 days without any discomfort. The larvae could tolerate the daily changes of 7-9°C. See adverse effects. Barracuda can also be adapted to changes in water quality, such as barracuda can still endure in dissolved oxygen of 0.9mg/L of water.
(2) Feeding Habits Barracudas have a wide range of feeding habits and are omnivorous fishes that are mainly feed on plants. It mainly uses benthic diatoms and organic debris deposited on the sediment surface, and also eats some filamentous algae, copepods, polychaetes, molluscs, and small shrimps. Under artificial breeding conditions, we also like to eat rice bran, bean cake powder, peanut cake powder, dried leeches and artificial diets. Barracuda feeding intensity, there is day and night, season, individual differences. In the daily cycle, both day and night feed, but usually the intensity of feeding before and after dawn and before and after sunset is greater than at night; during the growth cycle, barracuda 20-40cm body length feeding intensity; before the reproductive period, the intensity of ingestion Large, esophagus, and stomach are always full of food. During the reproductive and spawning seasons, they rarely eat and eat. From the seasons point of view, spring is not the beginning of the summer and autumn is the season of strong feeding, and in the winter, as the water temperature decreases, the fish enters the wintering period, when the fish eat very little or stop feeding.
(c) The migratory barracuda is a semi-migratory fish that has no long-distance migration. However, it can be used as a short-distance and small-scale migration movement with the season, water temperature and its own development. Squid often inhabits shallow sea or estuary depth of 1-16m, when the weather becomes cold, then swim to the deep winter. But individual winters also occur in deeper bays and shallow seas. Squid spawned in deeper sea areas, and the hatched young fishes drifted to the near-shore estuary with the tide and stayed at the salt-freshwater confluence to feed and grow. Barracudas generally grow in the coastal waters and form large groups to spawn in the bays and estuaries on an annual basis. From June to July, a large number of juvenile fishes appeared on the coast of the Yellow Sea and Bohai Sea and entered the mouth of the river. During the cold days, they swim to deeper sea areas for winter.
III. Growth (a) Growth of barracuda According to the report of Li Mingde et al. (1978): The barracudas collected in the Qikou area of ​​Hebei Province have a maximum age of 8 years, a maximum body length of 720 mm, and a weight of 4600 g. The growth of barracuda varies between different age groups. In the same age group, the range of body length and weight changes are also larger. In general, when the young shuttle grows more slowly, the average weight is 50g, and it enters the peak of growth from the second year until the 6th year, especially 3 to 5 years old, and grows most rapidly. Slow down after age 6. The fullness and fat accumulation coefficient of each age group of barracuda were the highest between 1 and 2 years old, and then decreased with age. This change is related to the development of gonads in marine barracudas. Because the gonads of 1-2 years old mullets are not yet mature, their food intensity is the strongest. The fullness of the stomach is highest in the sac, and fat accumulation is more, so the fullness is higher.
After the 3rd and 4th instars, the gonads of the barracudas gradually matured and consumed a lot of fat due to the nutrients needed to supply the gonadal development. So in barracuda culture, the winter of the second and third year is sold as commercial fish, and the value of food is the highest. Coupling coefficient (%) = fat weight / (body weight - visceral weight) 100 Barracuda female and male sex differences in growth, in the young age is not obvious, but as soon as the gonads begin to mature, it is significantly reflected, 4-year-old female Fish, regardless of body length, body weight, and fullness, are larger than males. It can be seen that females of barracudas grow faster than males. The growth rate of barracuda is greatly affected by the food environment. The proper amount of individuals is mixed in the shrimp pond, and its growth is much faster than that of the natural sea area.
Polysaccharides are polymeric carbohydrate molecules composed of long chains of monosaccharide units bound together by glycosidic linkages, and on hydrolysis give the constituent monosaccharides or oligosaccharides. They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch and glycogen, and structural polysaccharides such as cellulose and chitin.
Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their monosaccharide building blocks. They may be amorphous or even insoluble in water. When all the monosaccharides in a polysaccharide are the same type, the polysaccharide is called a homopolysaccharide or homoglycan, but when more than one type of monosaccharide is present they are called heteropolysaccharides or heteroglycans.
Natural saccharides are generally of simple carbohydrates called monosaccharides with general formula (CH2O)n where n is three or more. Examples of monosaccharides are glucose, fructose, and glyceraldehyde. Polysaccharides, meanwhile, have a general formula of Cx(H2O)y where x is usually a large number between 200 and 2500. When the repeating units in the polymer backbone are six-carbon monosaccharides, as is often the case, the general formula simplifies to (C6H10O5)n, where typically 40≤n≤3000.
As a rule of thumb, polysaccharides contain more than ten monosaccharide units, whereas oligosaccharides contain three to ten monosaccharide units; but the precise cutoff varies somewhat according to convention. Polysaccharides are an important class of biological polymers. Their function in living organisms is usually either structure- or storage-related. Starch (a polymer of glucose) is used as a storage polysaccharide in plants, being found in the form of both amylose and the branched amylopectin. In animals, the structurally similar glucose polymer is the more densely branched glycogen, sometimes called "animal starch". Glycogen's properties allow it to be metabolized more quickly, which suits the active lives of moving animals.
Cellulose and chitin are examples of structural polysaccharides. Cellulose is used in the cell walls of plants and other organisms, and is said to be the most abundant organic molecule on Earth.It has many uses such as a significant role in the paper and textile industries, and is used as a feedstock for the production of rayon (via the viscose process), cellulose acetate, celluloid, and nitrocellulose. Chitin has a similar structure, but has nitrogen-containing side branches, increasing its strength. It is found in arthropod exoskeletons and in the cell walls of some fungi. It also has multiple uses, including surgical threads. Polysaccharides also include callose or laminarin, chrysolaminarin, xylan, arabinoxylan, mannan, fucoidan and galactomannan.
Polysaccharide Series,Cordyceps Polysaccharide,Hericium Erinaceus Polysaccharide,Goji Polysaccharide
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