What Is Shrimp Aquaculture?

An industry that uses artificial breeding for shrimps with higher economic value. Farming methods include pond culture, harbor culture, and cage culture. There are also polycultures such as fish, shrimp, and shellfish. The cultured species are mainly prawn oriental shrimp and monodon prawns in seawater shrimp, and there are also farmed lobsters in southern China. In freshwater shrimp, there is Macrobrachium rosenbergii.

Shrimp farming

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An industry that uses artificial breeding for shrimps with higher economic value. Farming methods used

More than 200 years ago, coastal residents of Hebei, Guangdong and other provinces in China built banks and set up sluices on the banks. The high water level at high tide was used to incorporate fish and shrimp seedlings for polyculture, and harvested in late autumn. This method is completely restricted by natural environmental conditions, and the yield is very low and unstable. Similar breeding methods are also found in Southeast Asia and Central America. In the 1940s, Fujimoto Yoshitomo successfully cultivated the world's first shrimp seedlings, which laid the foundation for the development of world shrimp breeding production. In the early 1960s, fully controlled shrimp farming was already possible on a small scale, and by the 1970s a more complete set of seedling and breeding techniques was gradually used for production. Freshwater prawn farming research started with Lin Shaowen. He created the artificial breeding and breeding methods of Macrobrachium rosenbergii in the 1960s and has now been promoted in many countries around the world. Studies on the cultivation and life history of freshwater shrimp larvae in China have begun as early as the 1930s and 1940s. Research on marine shrimp farming began in 1953. In the late 1950s and early 1960s, Chinese prawn larvae were cultivated under completely artificial control. Large-scale artificial seedlings began in the late 1970s, and the situation of relying on natural seedlings ended in the early 1980s.

About 4/5 of the world's shrimp farming production is produced in the tropical and subtropical regions of the Indian Ocean-Western Pacific Coast. In addition to China, Thailand, India, and Japan, which have breeding traditions, more than 20 countries, including the United States, Canada, Honduras, Australia, and France, have established productive shrimp farms and professional research institutions. In addition to prawns, there are more than 20 species such as spring-tailed white shrimp, northern prawns and Macrobrachium rosenbergii. In addition, there are several types of lobsters (Panulirus spp) and lobsters (Homarus spp).

The breeding method mainly includes two stages of seedling raising and growing.

Seedlings for nursery shrimp breeding can be directly harvested from natural breeding grounds (estuaries or shallow seas) or incorporated using tide water, or artificially cultivated. Macrobrachium and other shrimp breeding seedlings must be artificially cultivated. There are many kinds of nursery facilities, such as earth ponds, cages, cement ponds and polyester sinks, and cement ponds and polyester sinks are the main ones. The area is generally only a few square meters to dozens of square meters. Environmental conditions are easy to control, and the emergence rate is generally higher than that of large water bodies. ^[1]

Breeding and maturation of broodstock. Broodstock for nursery can be directly caught from the pregnant female shrimps in the sea area, or they can be mated and spawned by breeding mature shrimps. The mating and spawning of Macrobrachium rosenbergii and other true shrimps occurs when the females mature and shed their skin. Prawns are mated before spawning, and females carry sperm pods to fertilize during spawning; therefore, males do not need to participate in the fertilization process. Measures such as raising the water temperature or removing the eye stalk (destroying the glands that secrete ovarian development-inhibiting hormones from the female) can promote broodstock gonad development and maturity and early spawning.

Treatment of nursery water and water quality monitoring. In order to ensure the ovulation and survival of larvae, seedling water is usually subjected to sedimentation, filtration and disinfection. The process includes precipitation, chlorination, disinfection, water filtration, temperature pre-adjustment, and so on. If the concentration of harmful heavy metal ions (such as zinc, copper, lead, cadmium, mercury, etc.) is found to exceed the normal seawater content, an appropriate amount of sodium EDTA should be added to degrade its toxicity. Water quality and salt testing items generally include water temperature, salinity, pH, ammonia nitrogen content, harmful protozoa, light and seawater transparency. The monitoring standard varies with different shrimp species. For example, the suitable salinity range for Chinese shrimp breeding is 25-30, pH 7.6-8.3, and ammonia nitrogen value does not exceed 0.1ppm. In addition, ventilating and changing water to the pool water are also necessary measures to ensure water quality conditions. In order to prevent shrimp disease in the nursery process, drugs such as antibiotics are usually added to the pond water.

Feeding of larvae. The quality of bait and the amount of bait are directly related to the survival and development of shrimp larvae. The larvae's bait is mainly micro-plankton, but the requirements for bait are different at different development stages. For example, Chinese prawns do not feed at the nauplii stage; larvae mainly feed on diatoms and other unicellular algae, but since the second stage larvae, they also have a tendency to eat micro-plankton (such as rotifers); Feeding habits in the larval stage are dominated by zooplankton. Therefore, it is necessary to adjust the type and quantity of bait in time according to different development stages.

There are three main ways to cultivate: extensive cultivation. Ie fish farming. Fish and shrimp polyculture is carried out using abundant natural bait on the coast. Generally do not feed or only a small amount of supplementary feed. The area of the breeding pond is large, but the yield is very low. It is mainly found in Southeast Asian countries such as the Philippines and Thailand, as well as tropical American countries such as Ecuador and the southern coast of China. Due to the abundance of fish and shrimp seedlings in these sea areas, the water temperature is high, and the natural conditions are superior, breeding operations can be carried out throughout the year, and some harvest 3 to 4 times a year. Many of the extensive shrimp farms in China have been fully planted with artificial seedlings, and some have also been supplemented with bait. The annual output is about 100 kg / ha. The main advantages are that no feeding is required, management is simple, and cost is low. High-density intensive cultivation. Also called intensive farming. Pools made of cement or polyester. Oxygenation is carried out by running water, water spray or aerator, automatic water quality monitoring is implemented, artificial feeding is fully fed and artificial shrimp seedlings are placed at high density, and the annual output can reach 10-40 tons / ha. However, the area of the breeding pond is small and requires a high level of technology and advanced equipment. It is mainly found in Japan, the United States, Ecuador, Mexico, South Africa and Southeast Asian countries. Semi-intensive culture. Somewhere in between. Earth ponds are generally used. Where conditions permit, aeration equipment is also used to alternately feed artificially mixed bait and live bait. The amount of seedlings released is slightly lower than that of high-density intensive cultivation, which is the main cultivation method.

Management during the growing period mainly includes water quality monitoring and feeding, water patrol, etc. Prawns with a body length of 1 to 2 cm account for about 150 to 200% of body weight; 4 cm account for 50%, 7 cm account for 20%, and 12 cm or more account for only 5 to 10%. However, the actual amount of bait depends on the temperature of the water, the number of basic bait organisms in the pond, and especially the residual situation of artificially bait. The water depth of shrimp ponds is generally required to be more than 1.5 meters, and the daily water replacement volume should account for at least 15% of the total water in the pond. When changing the water, the principle should be to discharge the water first, then to accept the water, and to change the water later in the evening. Pond patrol is the most direct and reliable way to discern shrimp dynamics with the naked eye. Pay attention to the color of pond water and substrate, odor change, bait situation, shrimp behavior (such as "floating head"), and the growth and decline of enemy organisms, etc. Wait. In order to prevent the breeding of enemy organisms and the aging of the bottom of the pond, after the shrimp harvest is completed every year, the water in the pond must be drained in time, the top black soil should be dug, the bottom of the pond be plowed and compacted, and exposed and frozen in the winter; the shrimp fry are officially Before entering the pond, clean the pond with fish vine extract, croton and tea seed cake. Practicing early spring water for shrimp culture can prevent competing organisms and harmful fish from entering the pond and prolong the growth and reproduction time of basic bait organisms in the pond. ^[1]