Special Topics on Silkworm Culture

General situation of Bombyx mori

Sand silkworm (Nereid) English name-Clamworm, belongs to the annelid phylum, hairy class, commonly known as sea worms, sea maggots, sea centipedes, sea leeches. As the object of capture and culture, most of them are large species of genus PerinereisKinberg, NeanthesKinberg and so on. For worm-shaped, silkworm body growth up to more than 10 cm, some species up to more than 20 cm. Cross section orbicular or slightly flattened, with many segments. The body is divided into head, trunk and tail. The head is composed of cephalic and peri-oral segments, with tentacles, eyes and mouth, and a kiss in the mouth, which generally has many small dark brown teeth.

The back of the head is the trunk cadre, and there are verrucous feet with bristles on both sides of each segment of the trunk. The bristles have poisonous glands, and the skin is red, swollen and painful. The tail, also known as the anal segment, has anus and anal tentacles. Bombyx mori is rich in nutrition, which is not only a feeding organism for fish and shrimp, but also an excellent bait. Coastal residents of Fujian, Guangdong and Guangxi also regard sand silkworms with mature gonads as nutritional treasures. After drying, the soup is as white as milk, with a delicious taste and high concentration, which is known as "natural monosodium glutamate". Deep-fried, crisp and crisp, for wine and food. Sand silkworms sell well both at home and abroad.

Farmed species:

Because of its various ways of reproduction, we are unable to raise some species. To put it simply, what can be raised now is several species of Bombyx mori (genus) and Bombyx mori (genus). There is another kind, the Japanese call it "golden sand silkworm" commonly known as "red sand silkworm", in fact, there is a kind of red sand silkworm called rock worm, the price is as high as 10,000 yen per kilogram, it is a valuable species, and it is also being raised on a trial basis. Want to raise which kind of sand silkworm, first of all, according to the bottom, if the clay bottom can not raise rock worms, and then for what use, such as to raise good shrimp, can only raise sand silkworms.

Ecological habits and harvesting

Ecological habits:

The silkworm lives in the mud and sand sediment of the intertidal zone, digs into U-shaped holes and hides in it, moves with the rise and fall of the tide, goes out day and night, and falls out of sand when feeding. The larvae mainly feed on single-celled algae, while benthic caves use animal and plant fragments and debris as bait, which can effectively utilize the protein in the sludge. The ability to adapt to temperature and salinity is strong.

Most of them are dioecious, but there is no obvious reproductive system, and gonads are formed when they are sexually mature. The shape and body color of most marine sand-producing silkworms change before reproduction, which can be distinguished that the female-turquoise, the male-the whole is milky white, and the feet are red. When the full moon, groups travel to the sea, some male and female chase, there is the phenomenon of wedding dance. In vitro fertilization. The mature eggs are spherical, turquoise and sinking eggs with a diameter of 75 Mel 150 microns. The fertilized egg grows into an adult through the developmental metamorphosis stages of early embryo development, trochophore larva, verrucous foot larva and rigid joint larva.

There are two ways to collect and catch silkworms.

A dense net is used to catch sexually mature individuals who mate in a cluster of water. Work at night during the spring tide in the breeding season, and most of the captured sand silkworms are for food. Digging in the intertidal zone. The sand silkworm burrowing in the sand is about 25mur40 cm. When the tide goes out, it carries a shovel, spade or hoe to find the hole, and dig quickly before the silkworm is alerted and retreat to the depths. Be careful not to break the silkworm body, and it is not easy to store the remains. The collected sand silkworms should prevent the sun and rain, so as not to affect the survival rate.

Economic value of Bombyx mori culture:

Silkworm culture can improve the bottom quality of the pond, control environmental pollution and promote the virtuous cycle of mariculture. Bombyx mori is the main protein feeding object of fish, shrimp and crabs. The rise and fall of natural Bombyx mori resources is directly related to the abundance and apology of marine fisheries. Also known as "omnipotent bait", and is a high-quality sea treasures, has entered a high-end banquet. The requirement of breeding sand silkworm is not high, as long as the seawater barren beach is simply surrounded by dike, it can be reared, the feed is coarse and miscellaneous, the source is wide, and a large number of nutrients can be obtained in the sea water.

Long-term habit of only catching but not raising, so that natural resources have been seriously damaged, has to be raised to the point where it is necessary to raise, so now the breeding profit is considerable. If you invest about 200 yuan per mu, you can make a profit of 2000mur3000 yuan. And it belongs to a single investment that can be rolled and developed year by year for long-term enjoyment. It should be said that it is a shortcut to get rich along the coast.

Culture methods:

Factory artificial breeding

It was first seen in Japan in the 1980s, mostly artificial seedling breeding was carried out first, and then seedling stocking was carried out. Most of the specific methods were carried out in artificial indoor ponds (grooves). The seedlings were not covered with sand, while the seedlings were cultivated with coarse sand of about 30cm. Water every day, bait 2mi 3 times, and inflated. In this way, as long as the water supply is timely, the temperature is suitable, the density is reasonable, and the bait is suitable, it only takes half a year to develop the commodity, and the output is generally 10 kg per ping (about 3 kg per square meter).

Extensive pond culture

The key point is to adopt artificial (or semi-artificial) breeding and large area stocking in soil ponds, and to make use of shallow pool depressions which are not suitable for feeding shrimp at present. In view of the large area of these waters, most of them are initially developed, and the pest removal is poor, and the sand silkworm itself is a kind of bait organism (including adult larvae), so the water intake in the pond must be more rigorous than that of stocking fish and shrimp, so as to prevent it from being attacked by many kinds of creatures. affect survival and yield. Judging from the current performance, as long as the density is appropriate and the management is proper, the yield per mu can be more than 50 kg.

Proliferative tidal flat stocking

The work is carried out from the point of view of increasing resources. It is reported that the artificial rearing of sand silkworm larvae in the natural sea area (intertidal zone) of Shandong and Liaoning has achieved a gratifying effect of increasing the yield by 75 times, and the method is also very simple. the social and ecological benefits are very significant.