Detailed Explanation of Key Techniques for Soft-Shelled Turtle Farming in Outdoor Ponds

The so-called healthy ecological farming of soft-shelled turtles refers to selecting a scientific farming management model based on the physiological and ecological requirements needed for the normal growth and activity of soft-shelled turtles, and providing the most suitable farming environment under human control, so that the turtles' activities and functions remain normal, their disease resistance and stress response capacity are improved, production and environmental resources are used most effectively, and they grow healthily and rapidly in a good ecological environment. Below, based on the actual farming conditions of soft-shelled turtle farmers in recent years, we briefly discuss healthy ecological farming techniques for soft-shelled turtles in outdoor ponds, for the reference of soft-shelled turtle farmers.  

Soft-Shelled Turtle Farming Techniques in Outdoor Ponds

1. Do a good job of pond cleaning and disinfection: newly excavated ponds can simply be disinfected with conventional quicklime; for soft-shelled turtle ponds that have been used for several years, the pond water should be drained during the idle winter period and left to freeze and sun-expose, then 20-30 days before stocking, cleaning and disinfection should be carried out. Generally, quicklime is still better for pond clearing, as it can both sterilize and improve the bottom substrate, buffering water quality changes during the farming process. About 10 days before stocking, fill the pond with water and disinfect the water body with chlorine dioxide or strong chlorine powder, etc., and appropriately apply biological fertilizer water essence and fermented organic fertilizer. For soft-shelled turtles, stocking in fertilized water is very beneficial, as it can create a better concealed environment for the turtles, reducing mutual biting and the occurrence of disease.  

2. Ensure the quality of turtle seed: for outdoor pond stocking, it is best to choose local Chinese soft-shelled turtle (Pelodiscus sinensis) or the Japanese strain of Chinese soft-shelled turtle. If using turtle seed raised in greenhouses, it is best not to separate or harvest them midway during the entire greenhouse rearing process, and to use as few antibiotics as possible or none at all. Such high-quality turtle seed will fare relatively smoothly in outdoor pond farming, grow quickly, yield high output, and produce a high proportion of large-sized commercial turtles.  

3. Control stocking density and increase stocking size: based on farming experience, for ecological farming in outdoor ponds, it is best to first intensively rear hatchling turtles in small ponds until they reach a size of 30-50 g each before stocking. Such seedlings have a stronger constitution, easily adapt to changes in the outdoor pond environment, and improve the survival rate of farming; by the second year of rearing, 70%-80% can reach commercial turtle size. If aiming to raise them to commercial size within the same year, the stocking size should preferably be 250-350 g each. The suitable stocking density is 1.5-3.0 turtles per sq m (1000-2000 turtles per mu); when polyculturing fish and turtles or shrimp and turtles, the stocking number of turtle seed is generally kept at 300-600 turtles per mu.  

4. Strictly control feed quality: currently, there are many and varied feed manufacturers and brands. Healthy soft-shelled turtle farming must involve feeding high-quality feed, and full-price compound feed produced by manufacturers with solid reputation and quality should be selected. First, the feed to be fed must be fresh and not deteriorated; after processing, it should not be stored for too long, and the pellet size should be appropriate. Second, strictly control and adjust the daily feeding amount; the daily feeding amount is mainly determined by the turtle's feeding situation and changes in weather, temperature, and water quality.  

Pay Attention to Water Quality Regulation  

1. The water body of soft-shelled turtle ponds is required to be slightly alkaline, with a pH value of 7.5-8.5. It is best to apply quicklime once a month in between, at a dosage of 10-15 g per cubic m  

2. Maintain a certain fertility in the water quality, with transparency kept at 25-30 cm, and water color preferably yellow-green or tea-brown;  

3. For water quality regulation and substrate improvement, currently the use of beneficial microbial preparations to cultivate and regulate water quality has a relatively good effect, and can improve the stability and self-purification capacity of the water body. Generally, Baoyu'an (compound microbial preparation), Huoshuibao (Bacillus), EM bacteria, etc. can be used to reduce the content of ammonia nitrogen and nitrite in the water and effectively decompose organic matter and other harmful substances in the bottom layer;  

4. The water level should be kept stable, and water changes should mainly be by adding water. Frequent water changes easily cause stress reactions in soft-shelled turtles and disrupt the original ecological balance; large-scale drainage and irrigation must be avoided.  

6. Implement multi-species polyculture to maintain water body biodiversity. Multi-species polyculture is an effective means of biological disease prevention and a very effective preventive method. It can overcome the drug resistance produced by long-term and large-scale use of chemical drugs or antibiotics, and can also avoid the side effects and environmental pollution caused by them, promoting the mutual growth of various organisms. In soft-shelled turtle ponds, aquatic plants can be appropriately planted, and species such as freshwater shrimp, river snails, silver carp and bighead carp, yellow catfish, Hemibarbus maculatus, and silver crucian carp can be polycultured to regulate water quality and improve the substrate. The number for supplementary stocking should not be too many, generally 20-50 individuals per mu.  

Emphasize Prevention and Comprehensive Control  

Based on the disease characteristics at different growth stages of soft-shelled turtles and daily observation, this is the focus of good preventive work.  

1. Normally disinfect once every 20 days or so. Disinfectants include quicklime, chlorine dioxide, sodium trichloroisocyanurate, and other safe and environmentally friendly drugs, used in alternation  

2. Regularly add enzyme-producing probiotics, soft-shelled turtle multivitamins, fish and shrimp supplement (anti-stress response), immune polysaccharides, florfenicol, and virus-star and other Chinese herbal preparations to the feed in alternation to enhance the immunity of soft-shelled turtles;  

3. Prevent stress reactions, especially when environmental factors such as climate and water temperature change obviously or suddenly, such as when greenhouse soft-shelled turtles are transferred to outdoor pond farming, during the plum rain and typhoon rainstorm seasons, and in high-temperature weather, etc. Disease prevention and water quality regulation should be done promptly to prevent the enhancement of stress reactions in soft-shelled turtles, which may lead to endocrine disorders and cause disease. Especially when greenhouse soft-shelled turtles are transferred to outdoor ponds, the time of leaving the greenhouse should not be too early; it is best from late May to early June, when the water temperature of open-air ponds is stable above 25°C and there have been more than one consecutive week of fine weather. At this time, greenhouse soft-shelled turtles start eating quickly after leaving the greenhouse and have fewer diseases. Stocked turtle seed must undergo body disinfection, and it is best to transport them with water.  

At present, the main diseases in outdoor pond soft-shelled turtle farming include: gill gland inflammation, white plastron disease, red neck disease, water mold, skin rot, furuncle, perforation, white spot, white spot disease, etc. Among them, the most harmful are soft-shelled turtle gill gland inflammation and white plastron disease. Both diseases are mainly caused by viruses, have a long incubation period, and once infected, acute outbreaks will cause large-scale disease and death. The epidemic period is mainly from June to August, and the main targets are juvenile and adult turtles. Next are skin rot and perforation disease caused by bacterial infection, etc. The control methods for these diseases are introduced below for reference.  

Main Control Measures for Soft-Shelled Turtle Gill Gland Inflammation  

1. First, use chlorine dioxide, quaternary ammonium salt iodine preparations, or trichloroisocyanuric acid, etc. to disinfect the water body of the turtle pond;  

2. Feed fresh high-quality bait, and promptly add fish and shrimp supplement, Fuleixing, virus-star and other Chinese herbal medicines and clindamycin, fosfomycin and other antibacterial and anti-inflammatory drugs to the feed, for a course of 5-7 days. If the condition is severe, feed another course;  

3. After the condition stabilizes, add enzyme-producing probiotics or Baoyu'an—attractant type and other microbial preparations and immune enhancers (such as fish and shrimp supplement, licorice polysaccharide, soft-shelled turtle multivitamins, glucan, etc.) to the feed for 10-15 days or longer, to enhance the resistance of the turtles;  

4. 3-4 days after water body disinfection, promptly add fresh water and splash Baoyu'an, Huoshuibao (Bacillus), EM bacteria and other beneficial microbial preparations to cultivate and regulate water quality, maintaining the stability and balance of algal phase and beneficial microbial population numbers in the water body.  

Comprehensive Prevention and Control of White Plastron Disease (Hemorrhagic Intestinal Necrosis)  

1. Pay attention to quarantine and select high-quality seedlings;  

2. Disinfect the water body regularly;  

3. Feed high-quality feed and strictly control the feeding amount;  

4. Usually emphasize prevention. After disease onset, promptly add virus-star and fish and shrimp supplement, Vb (0.2% of feed amount) or Banlangen, Kushen, Chuanxinlian, Huzhang, or Banlangen and Sanhuang powder mixture (1% of feed amount) to the feed, which has a certain control effect.  

Prevention and Control of Skin Rot  

At disease onset, first a certain area of skin on the body surface becomes inflamed and swollen, and the tissue at the inflamed area gradually necroses, turning white or yellow. Then the affected area forms an ulcer, and as it gradually enlarges, the muscle and bone become exposed. In severe cases, the bone of the neck is exposed, the limbs rot away, and the claws fall off.  

1. Reasonable stocking density;  

2. Regular water body disinfection;  

3. At disease onset, disinfect with chlorine dioxide, and at the same time add enrofloxacin or florfenicol and fish and shrimp supplement to the feed;  

4. Using the pure Chinese herbal compound preparation “Biebingning” (Sanhua powder), decocted in water and splashed over the whole pond and mixed into feed, can restore food intake in a short time and effectively control the spread of the disease.  

Prevention and Control of Perforation Disease  

In the early stage of disease onset, white scabs appear on the back, plastron, and marginal scutes of the turtle, with diameters ranging from 0.2-1.0 cm, with bleeding around them. After the scab is picked open, perforation of the shell can be seen, and the perforation site bleeds continuously. Scabs that are not picked open soon fall off on their own, leaving a small hole at the original scab site, with inflammation at the edge of the hole and blood flowing out under light pressure; in severe cases, the inner cavity wall can be seen. The prevention and control methods are the same as for “skin rot.”

In the process of farming soft-shelled turtles, the most important thing is disease prevention. Only by controlling soft-shelled turtle diseases well can their output be increased and greater profits be obtained. Therefore, there are also many techniques in soft-shelled turtle farming, and mastering certain farming techniques can help farmers avoid many detours.