Giant freshwater shrimp
In terms of maximum individual size and growth rate, there is a great range of variation between species, Macrobrachium rosenbergii, Macrobrachium americanum (M. americanum), Macrobrachium rosenbergii (M. carcinus), Macrobrachium malcolmsonii (M. malcolmsonii), Macrobrachium Ganges (M. choprai), Macrobrachium Africanus (M. vollenhovenii) and Macrobrachium bulimia (M. lar) are the largest known species. . According to Bate's 1868 treatise, all farmed freshwater shrimps currently belong to the largest genus in the family Longbrachiidae, namely Macrobrachium. About 200 species have been described, most of which spend part of their life cycles in fresh water. In terms of maximum individual size and growth rate, there is a large range of variation between species, including Macrobrachium rosenbergii, Macrobrachium americanum (M. americanum), Macrobrachium carcinus (M. carcinus), Macrobrachium malcolmsonii (M. malcolmsonii), Macrobrachium (M. choprai), Macrobrachium (M. vollenhovenii) and Macrobrachium (M. lar) are the largest known species. Macrobrachium rosenbergii (M.rosemberii) is the largest freshwater shrimp in the genus Macrobrachium. The largest male shrimp can reach 40 centimeters in length and weigh 600 grams. It is mainly distributed in tropical waters in Malaysia, Thailand, Philippines, Indonesia and India. It is large in size, eats a variety of foods, grows quickly, and is easy to raise. After Chinese-American Lin Shaowen studied its life history in the early 1960s, artificial breeding immediately became successful. After mating and spawning in natural waters, the egg-bearing female shrimps immediately descend to the river to live in brackish waters until they mature. The larvae must grow in water with a certain salinity to carry out normal growth and development. After they grow into young shrimps, they move up the river and live in the upper reaches of rivers or lakes until they lay eggs. During artificial breeding, the suitable salinity of seawater in the pool is 12 to 14, and the suitable water temperature is 24 to 30°C.
Natural origin of freshwater shrimp
Freshwater shrimp species of the genus Macrobrachium are distributed in tropical and subtropical areas around the world. Holthuis (1980) provided valuable information on the distribution of Macrobrachium species, local names, habitats and maximum commercial sizes.
They live in most inland freshwater areas, including lakes, rivers, swamps, ditches, canals and ponds, and estuaries. Although some species complete their life cycles in inland saltwater and freshwater lakes, most species require brackish water during the early stages of their life cycles (and therefore live in bodies of water directly or indirectly connected to the ocean). Some species prefer clear rivers, while others thrive in extremely turbid water. Macrobrachium rosenbergii belongs to the latter category.
In terms of maximum individual size and growth rate, there is a great range of variation between species, Macrobrachium rosenbergii, Macrobrachium americanum (M. americanum), Macrobrachium carcinus (M. carcinus), Macrobrachium martensi Macrobrachium (M. malcolmsonii), Macrobrachium Ganges (M. choprai), Macrobrachium Africanus (M. vollenhovenii) and Macrobrachium vulgaris (M. lar) are the largest known species. Cauque river prawn naturally grows in the watersheds of western America, while painted river prawn grows in places connected to the Atlantic Ocean. Ganges river prawn grows in the Ganges and Brahmaputra river systems. Monkey river prawn is native to the Marquesas Islands region from East Africa to the Pacific Ocean (and introduced to Hawaii). Macrobrachium martensi (monsoon river prawn) grows in rivers in Bangladesh, India and Pakistan. The giant river prawn is native throughout South and Southeast Asia, as well as northern Oceania and the islands of the western Pacific. African river prawns are naturally distributed in West Africa from Senegal to Angola.
Many Macrobrachium species have been moved from their original habitats to other parts of the world, initially for research purposes. Macrobrachium rosenbergii is the most commonly used species in commercial farming and is therefore also a species introduced by many countries. After the species was introduced to Hawaii from Malaysia in 1965, the pioneering work there by Ling (1969) was developed by Fujimura and Okamoto (1972) into a large-scale postlarval production method that was adopted on almost every continent , used for breeding. Macrobrachium rosenbergii is now farmed in many countries, with the main producing countries (>200 metric tons) being Bangladesh, Brazil, China, Ecuador, India, Malaysia, Taiwan Province of China and Thailand (FAO 2002). According to reports, in 2000, more than 30 other countries produced this variety. According to New (2000), Vietnam is also a major producer. In addition, Macrobrachium rosenbergii also plays an important role in capture fisheries, such as in Bangladesh, India and several other countries in Southeast Asia.