Methods for Pond Culture of Tubifex Worms and Key Points of Breeding Technology

For breeding premium aquatic products, feed is an important material foundation and restrictive factor, as it determines the success or failure of the cultured species and the level of economic benefit. Tubifex worms reproduce quickly and have high nutritional value (dry matter contains 62% crude protein, total essential amino acids reach 35%, nitrogen recovery rate reaches 98%), and are the preferred opening bait for many aquatic animal fry and fingerlings. They are also the main food for bottom-dwelling fish such as sturgeon, yellow catfish, carp, crucian carp, loach, giant salamander, and swamp eel. Among aquatic worms, the species suitable for culture include: Branchiura sowerbyi and Limnodrilus hoffmeisteri. Culturing tubifex worms well can provide long-term stable high-quality animal feed for aquatic product farming, reduce farming costs, and improve farming benefits and product quality. Here we introduce a simple and easy pond culture method for tubifex worms.

I. Life and Reproductive Habits of Tubifex Worms

Tubifex worms are not large individually, about 100 mm in length, but the population yield is relatively high. The difference between Branchiura and Limnodrilus is that the former has tail gills, with the tail end often exposed outside the mud, swinging with the water for respiration, and trembling faster when oxygen is insufficient; the latter has no tail gills. Tubifex worms prefer to live in mud of micro-muddy waters rich in organic matter, generally lurking 10 cm to 25 cm below the mud surface, and burrowing deep into the mud at low temperatures. Tubifex worms prefer darkness and fear light, cannot be exposed to sunlight, and feed on mud, absorbing organic humus, bacteria, and algae from it. Tubifex worms reach sexual maturity in about 2 months, are hermaphroditic, with cross-fertilization, and eggs are wrapped in sac-like cocoons formed by transparent gelatinous membranes. Generally, one cocoon contains 1 to 4 eggs, or up to 7. During the reproductive period, each adult can release 2 to 6 cocoons. When water temperature is 22 to 32°C, the incubation period is generally 10 to 15 days, and the lifespan of artificially cultured ones is about 3 months.

II. Pond Culture Method

1. Pond Conditions

Build an ecological environment suitable for aquatic worms, requiring slight flowing water, loose soil, rich humus, and light avoidance. The pond can be newly dug or converted from a water pit connected to ditches. The area depends on need; 3 to 5 sq m (length-to-width ratio of 3:1 to 5:1) is suitable, with a water depth of 20 to 25 cm. The bottom should be built with loess or lime-sand mixture with good water retention, and inlet and outlet ports should be set up. Generally, the inlet and outlet should be separate, with water entering at one end and draining at the other. Before introducing the worms into the pond, the bottom mud must be cultivated well. It is best to dig fertile fish pond sludge and spread it on the pond bottom at a thickness of 10 cm, then add 7.5 to 10 kg of livestock and poultry manure or farmyard manure per sq m, and finally add fermented cake, bran, and distillers' grains.

2. Introducing the Worms into the Pond

The amount of introduced worms depends on water quality, mud quality, manure source, and season. When fertilizer sources and mixed feed sources are sufficient, the introduction amount is large and the yield is high. Generally, 0.25 to 0.5 kg of seed worms are stocked per sq m. After 30 to 45 days of culture, the daily harvest per mu can reach 10 to 15 kg, with a maximum of 48 kg.

3. Management

Maintain slight flowing water to keep the water fresh, with relatively high dissolved oxygen, accelerate the dissipation of metabolic products, and increase the worms' feeding and growth. Generally, the water flow rate should be 2 to 8 cm/second. The speed must not be too fast, as too fast a flow will wash away nutrients and worm cocoons, affecting output. After the worms are introduced, they should be fed once every 2 to 3 days. If concentrated feed is used, the feed conversion ratio is about 2.6; if pig or cow manure is used, the feed conversion ratio is 7.8 to 10.4.

4. Harvesting

At night, reduce the water flow or cut off the water, causing oxygen deficiency in the pond by the next morning or forenoon. The tubifex worms will then be forced to cluster into balls and float on the mud surface or rise to the water surface, and can be harvested with a scoop net.