Pond Fish Farming Basics and Key Aquaculture Techniques Explained

Pond fish farming refers to fish farming carried out in artificially constructed or naturally formed still-water ponds, also known as inland pond fish farming. Pond water bodies are relatively small, easy to control manually, and convenient to manage; comprehensive technical measures can be adopted for intensive farming to increase the yield per unit of water area. The production process is divided into four stages: fish fry are obtained through artificial breeding; in the same year or the following year the fry are reared into fingerlings; the fingerlings are raised for a certain period to become market-size fish; and some fish are further reared into broodstock. Depending on need, one may also specialize in only one of these stages of farming production. China ranks first in the world in pond fish farming area, yield per unit, and total output. The countries in the world that practice pond fish farming mainly include India, the countries of Southeast Asia, Japan, Russia, the United States, and others. The main farming techniques of pond fish farming include polyculture and dense stocking, rotational harvesting and restocking, daily management, and integrated operation.

Polyculture and Dense Stocking

Polyculturing and rationally densely stocking fish species with different habits, different feeding habits, or the same species of different sizes in the same pond is the core of China's pond fish farming technology. Silver carp and bighead carp live in the upper layer of the water body; grass carp and Wuchang bream live in the middle and lower layers of the water body; black carp, mud carp, common carp, crucian carp, tilapia, and others live at the bottom of the water body. When these different species of fish are polycultured in the same pond, not only can the stocking rate per unit area of the pond be increased, but because the various fish require different feeds, the various feed resources in the pond can be fully utilized, mutually beneficial relationships are produced, and eutrophication of the water body is also prevented and the pond's production conditions are improved. Polyculturing fish of the same species but different sizes allows large-size fingerlings to be produced while edible fish are being produced, thereby reducing the ponds needed for rearing fingerlings and expanding the rearing area for edible fish. Within a reasonable density range, as long as the water temperature is suitable, the water quality is good, the proportion of polycultured fish and the size of stocked fingerlings are appropriate, the feed is of good quality and sufficient, and the feeding and management are meticulous, the yield will increase.

Rotational Harvesting and Restocking

That is, stocking fingerlings in full once, and after rearing for a period, harvesting in batches part of the adult fish that have reached market size, then appropriately supplementing with fingerlings. Using this method can keep the density per unit of water volume in the pond at a suitable level at all times, thereby increasing the fish yield per unit area.

Daily Management

Controlling the color of the pond water is the main technical measure of daily management. Good water colors such as pea green and tea brown are a comprehensive indicator; they show that the phytoplankton in the pond water is dominated by high-quality populations such as cryptomonads, diatoms, and other algae. If these algae form blooms, it indicates that various nutrient salts are abundant, intermediate metabolic products decompose quickly, and the dissolved oxygen status is good. To keep the water color good, fertilizer must be applied at the right time and in the right amount, and new water must be added and pond water discharged. The feed is mainly aquatic plants, terrestrial grasses, and algae, supplemented with compound feed, oil cakes, grains, and bran, or field snails, shellfish, and others. Feeding should be timely, appropriate in amount, and at fixed points, so that the fish's feeding situation can be checked. The purpose of fertilizing is to cultivate plankton in the pond, mainly using poultry and livestock manure and green manure. In high-yield intensive ponds, because the fish stocking density is high and the amount of feed and fertilizer applied is large, the dissolved oxygen content is prone to decline, threatening the survival of the fish; new water or oxygen must be added in a timely manner to avoid the occurrence of fish pond collapses and fish gasping at the surface.

Integrated Operation

In China, pond fish farming is often the main activity, integrated with livestock and poultry raising, sericulture, vegetable growing, and other operations, so as to fully utilize agricultural natural resources and agricultural by-products and their processing wastes, save energy, maintain ecological balance, and improve economic benefits. For example, in Guangdong's mulberry dike, sugarcane dike, and fruit dike fish ponds, mulberries are planted on the fish pond dikes, mulberry leaves feed silkworms, silkworm droppings and silkworm pupae and other materials feed the fish, fish feces fertilize the pond, and pond mud fertilizes the mulberries, so that the fish, mulberries, and silkworms can all grow well, forming a benign-cycle artificial composite ecosystem of diversified operation in which water and land mutually promote each other.