Another important use of Nereis is as bait. Nereis is the most broad-spectrum bait for offshore fish and is known as the "universal bait" for sea fishing.
Red Nereis: The local name is "rock worm". It is 20 to 35 centimeters long. The adult head is purple-brown, with light blue or light green fluorescence, the trunk is reddish-brown, sub-cylindrical, the tail is flat and pink or light yellow, and there are thick bristles on the side. Fresh red Nereis is the best bait for Nereis because of its bright color and strong smell. The disadvantage is that the abdominal cavity of the fresh worm is enlarged, the body fluid is too much, and the hook is not attached. Long-distance fishing is easy to cause the bait and hook to go their separate ways.
Nereis: It is called "tube maggot" locally. Body length 15 to 20cm. The head is brownish green, the fluorescence is weak, and the trunk is flat, brittle, hard and easily broken, and it is yellowish brown. Hiding in a tubular channel woven with shells, stones and secretions, when disturbed, it quickly shrinks back to the depths of the beach, and generally only the heads of insects can be collected. The body color markings are slightly different from those of rock worms, and they are the fine products in the diet of Nereis.
Red centipede: locally called "red sand maggot". The body length is between 5 and 15 cm. Body color can be divided into pink and orange, and there is a red line extending from the head to the tail in the center of the back. It has a slender figure and well-developed bristles on its lateral feet. It has strict requirements on the living environment, only inhabiting beaches with clean soil and good water permeability, and rarely seeing serious sludge pollution.
Green centipede: locally called "black sand maggot", with a body length of 5 to 10 cm. Widely distributed, rich in the Yellow Sea and Bohai Sea. The body characteristics are different from those of red centipede, and the worm body is thicker and slightly shorter than the former. The body surface is blue-green or blue-yellow, depending on the soil color of the habitat. There is no obvious red line on the back, and the lateral foot bristles are tight and short. The advantage of using sea centipede as bait is that the bait has strong adhesion to the hook, strong peristalsis of live insects and obvious target, which is easy to attract fish to compete for the hook.
Nereis is rich in nutrition, which is not only a favorite bait for fish and shrimp, but also an excellent bait.
After the worms are dug up, they should be put in wooden boxes. If you fish on the shore, the wooden box should be buried in the sand to prevent it from being killed by the sun. After fishing, you can pour some seawater (not fresh water) and put the wooden box in the shade, so that the Nereis can survive for 2 or 3 days.
Preservation: after digging out the nereis, pick out the whole worm, put it in a vessel, sprinkle with white wine, quickly soak to death, drain the wine, sprinkle with salt according to the amount of 10: 1, stir well, put it into sawdust, (for the purpose of absorbing water), put it into a plastic bag, tie it tightly, put it in a refrigerator, and freeze it if necessary. The advantage of this treatment is that it can be stored for a long time without discoloration and hardening, which is no different from fresh bait. Nereis is also called dragon intestines, and Pingtan is commonly known as "Shatian". Found in the intertidal zone on the west coast of the island. Before eating, put fresh Nereis into fresh water to spit sand, insert it from the tail with bamboo chopsticks, dig out the internal organs and wash it with clear water. Stir-fry fresh products in the oil pan, and the meat is crisp and delicious. After dried, Nereis, also known as "dried dragon intestines", is golden and transparent in color, more mellow and sweet than fresh products, and is a famous dish for senior banquets. It is nutritious, and has the functions of stimulating appetite, improving eyesight, nourishing liver and spleen, invigorating stomach and moistening intestines. Pingtan people give bundles of dried nereis as precious gifts to relatives and friends.
Coastal residents in Fujian, Guangdong and Guangxi also regard nereis with mature gonads as nutritional treasures. The soup boiled after drying is as white as milk, extremely delicious and high in concentration, and is known as "natural monosodium glutamate". Crispy rosin is crisp after frying and is a delicious drink. Nereis is very popular at home and abroad. When Japanese fishing enthusiasts use Nereis as bait, they find that mosquitoes, flies and other insects will be poisoned and die after crawling on the corpse of Nereis. At the same time, they also found that anglers who use Nereis will have symptoms such as headache, nausea and vomiting, and abnormal breathing. An active substance named nereistoxin was isolated from Nereis in 1934. In 1964, it was found that this toxin had a special toxic effect on rice borers. According to the chemical structure of nereistoxin, it can be used as a series of analogues of agricultural pesticides, such as cartap, dimehypo, dimehypo, dimehypo, dimehypo, dimehypo and so on. , is a bionic synthesis, collectively known as nereistoxin pesticides, but also the first class of animal-derived pesticides successfully developed by human beings. Its characteristics can be summarized as the following six aspects.
1, broad insecticidal spectrum. It can be used to control a variety of leaf-eating pests and borers on various crops such as rice, vegetables, sugarcane and fruit trees, and some varieties also have good control effects on aphids, leafhoppers, planthoppers, thrips and mites.
2. It has many insecticidal effects. It has strong contact toxicity and stomach toxicity to pests, and also has certain internal absorption and fumigation effects, and some varieties also have antifeedant effects. It is lethal to adults, larvae and eggs, both quick-acting and long-lasting. Therefore, when used in the field, the application period is long and the control effect is stable.
3. The action mechanism is special. Nereis toxin insecticide and organophosphorus. Insecticides such as carbamate and pyrethroid are all nerve agents, but their action mechanisms are different. Its action site is cholinergic synapse, which inhibits the normal transmission of nerves, so that the nerves of pests will not bear fruit when stimulated by the outside world. When pests contact or eat drugs, worms will soon be slow and paralyzed until they die. But after poisoning, there were no symptoms of spasm or overexcitation. Because of the different targets, there is no cross-resistance problem with organophosphorus, carbamate, pyrethroid and other pesticides, and there is no cross-resistance phenomenon in pest control. Therefore, it is still effective to use nereistoxin pesticides to control pests resistant to the above three pesticides.
4, low toxicity and low residue. At present, the toxicity of the developed varieties to people and animals, birds, fish and aquatic animals is in the range of low toxicity and poisoning, and it is safe to use. It has little impact on the environment, is easy to decompose in nature after application, and has no residual poison.