How to Farm Freshwater Crabs? Summary of Key Farming Techniques for 2019

In recent years, the scale of freshwater crab farming has expanded year by year, and farming models have also been continuously innovated, developing in an ecological direction. Many people also want to get involved in crab farming in 2019. Below is a summary of the key points of freshwater crab farming techniques, hoping to provide everyone with a reference.

I. Environmental Requirements for Crab Growth

Crabs like to live in warm and humid places, so there are certain requirements for sunlight intensity. Crabs can only grow healthily and normally when the sunlight intensity is appropriate. Temperatures that are too high or too low will cause diseases in crabs.

II. Selection of Freshwater Crab Varieties

Generally speaking, it is necessary to select juvenile Chinese mitten crabs (Eriocheir sinensis) that have been self-bred or locally bred from the Yangtze River water system, with robust physiques, no diseases or injuries, uniform size, intact appendages, glossy shells, and strong vitality as crab seed. Avoid using juvenile crabs of unknown origin. This is the most important factor in farming large crabs and improving the survival rate.

III. Planting Aquatic Plants in Advance

The varieties of aquatic plants planted should not be limited to a single type but should be diversified. It is best to combine submerged plants, emergent plants, and floating plants with reasonable distribution to suit the various needs of river crabs. For submerged plants, options include tape grass (Vallisneria), Hydrilla verticillata, and Elodea. Emergent plants include reeds and wild rice stem grass. Floating plants include duckweed. The area planted with aquatic plants in crab farming waters should account for 50—60% of the water surface area.

Planting aquatic plants for crab farming has many benefits, such as:

1. Serving as natural, high-quality plant-based feed for crabs;

2. Providing hiding places for river crabs to rest and molt, making it harder for predators to find them and reducing mutual killing;

3. The photosynthesis of aquatic plants can increase dissolved oxygen in the water and absorb organic matter in the water body, preventing water eutrophication. It can purify water quality, maintain fresh water quality, and improve the aquatic farming environment;

4. In high-temperature seasons, aquatic plants can provide shade and cooling.

IV. Crab Feeding and Management

1. Releasing Seedlings

A two-year farming model can be adopted, which means purchasing crab seedlings in late May to early June, conducting extensive rearing in ponds, and by the end of the year they can be grown into juvenile crabs. In the second spring, these juvenile crabs are then released into the pond. Usually, the stocking size of crab seed is 100—200 per kg. Stock 300—500 per mu of water surface. Proper release can improve the harvest size and quality of river crabs.

2. Water Quality Control

When farming crabs in ponds, very high requirements are placed on the water quality used. Pond water needs to be disinfected. Bleaching powder should be used for chemical disinfection of the pond. Water quality must be kept clean to avoid water quality problems.

3. Crab Disease Prevention and Treatment

Crab disease prevention and treatment should adhere to the principle of prevention first, achieving early detection and early treatment. Prevent diseases before they occur, and treat them early when they do. Different methods should be adopted for prevention at different growth stages.