Precautions and Specific Operating Steps for Winter River Crab Farming

I. Seedling Soaking

In traditional methods, salt or potassium permanganate is used for soaking seedlings. Nowadays, many farmers soak crab seedlings in EM stock solution before stocking. The specific method is: dilute Yifuyuan EM bacterial liquid 200-300 times, then soak in it. Use an inflatable aerator pump for oxygenation, then place the crab seedlings into the water. The soaking time is 20-30 minutes. In water with sufficient oxygen and good bacteria, let the crab seedlings move freely, absorb and release water, and expel harmful substances from their bodies. This can significantly reduce the first and second molting mortality of river crabs. According to experimental statistics, the mortality rate of crab seedlings is reduced by 30%-40%.

II. Soaking and Mixing Feed

In the process of high-yield and high-efficiency river crab farming, the daily feed mainly includes fresh small fish, frozen sea fish, pellet feed, etc. In particular, fresh small fish and frozen sea fish contain a large amount of bacteria, which can easily cause enteritis in river crabs and pollute the water quality. In farming, on the one hand we adjust the feed structure, and on the other hand we use EM stock solution. The specific method is: dilute 1 kg of EM bacterial liquid 30-50 times, evenly spray it onto 200 kg of feed, pile and cover for 2 hours, then feed. If feeding fresh small fish or frozen sea fish, for every 100 kg of fresh small fish or frozen sea fish, after slicing, soak with 1 kg of Yifuyuan EM bacterial liquid diluted 200 times for 3 hours, then feed. This can significantly reduce the incidence of enteritis in river crabs and causes less pollution to the water body.

III. Water Quality Regulation

In the process of river crab farming, every year in May, when the temperature rises, the moss begins to die, the pond water gradually becomes thicker, and the water color becomes turbid, affecting the photosynthesis of aquatic plants. In severe cases, grass decay and water deterioration occur. At this time, 100 g of chlorine dioxide per mu should first be splashed over the whole pond for water disinfection, then EM bacterial liquid should be splashed over the whole pond. For water 1 m deep, use 1 kg per mu, and splash again at an interval of 15-20 days, so that beneficial populations form a dominant position in the pond, increase water transparency, and form fresh, lively, tender and refreshing high-quality farming water, so that aquatic plants can carry out normal photosynthesis, improve their ability to purify water quality, and ensure the smooth progress of river crab farming.

After using Yifuyuan EM bacterial liquid, river crabs have strong disease resistance, gain weight quickly, are large in size, have good quality, and show significant economic benefits, with output increased by about 30% and benefits increased by 20%-30%. At present, microbial preparations represented by Yifuyuan EM bacterial liquid have been applied quite widely in our city, and have shifted from the original publicity and promotion period to the period of active application by farmers. This is a strong guarantee for the development of ecological and efficient fisheries in our city and is of great significance for achieving sustainable development of fisheries.