Chengchi Lake, home to the stingray breeding project of the Changjiang Fisheries Research Laboratory, was originally a large-scale soft-shelled turtle farm. However, with a decline in the market price of turtles and reduced breeding efficiency, the monoculture system could no longer sustain operations. The key challenge became how to maximize production potential and improve economic returns within the existing pond conditions. In recent years, stingray farming has gained popularity, and the market for this species has become increasingly promising. Given that stingrays have similar water quality requirements to soft-shelled turtles and do not compete for food, an experiment was conducted to introduce stingrays into the turtle breeding ponds. The results were encouraging.
The experimental ponds were selected from the adult fish breeding pools of the turtle farm, numbered 1 through 8, covering a total of 8 acres. Each pond was approximately 1 mu in size, with a depth of 1.5 meters. The layout was spacious, oriented north-south, ensuring ample sunlight, good ventilation, and convenient drainage and irrigation. The environment was also quiet, ideal for aquaculture.
For the fingerlings, soft-shelled turtles, grass carp, silver carp, and white sturgeon were used, all produced on-site. Stingrays, however, were sourced from wild populations in nearby lakes around Jingzhou City. Stocking densities varied: soft-shelled turtles at 800 per acre (150–200 g each), grass carp at 10 per acre (250 g each), silver carp at 40 per acre (150–200 g each), and white sturgeon at 100 per acre (250 g each). Stingrays were introduced at four different densities: 4 kg, 8 kg, 10 kg, and 15 kg per acre. Any dead fingerlings within the first month were replaced immediately, and any deaths caused by human error or poor breeding led to the invalidation of the entire dataset for that pond.
Pond management involved regular disinfection and water quality control. Before stocking, each pond was limed and cleared of wild fish and frogs. Water transparency was maintained between 30–40 cm, with monthly water changes of 30–50 cm. Lime (40–50 mg/L) or bleach (1–1.5 mg/L) was applied every 10–15 days to maintain water quality.
Feeding was primarily focused on the soft-shelled turtles, following the "four definite" feeding method. The growth and health of all fish were monitored regularly, and feed amounts were adjusted accordingly. Stingrays, however, were not fed directly.
Disease prevention included regular lime application to maintain slightly alkaline water and monthly bleach treatments. No significant disease outbreaks were observed during the trial period.
Over the course of 150 days, from May 2000 to late October, a total of 347.5 tons of stingrays were harvested without affecting the yields of other species such as soft-shelled turtles, grass carp, silver carp, and white sturgeon. On average, each mu yielded 46.8 kg of stingrays.
The study found no significant differences in turtle production or the yield of other fish species between the stingray-integrated ponds and non-stocked ones. However, the size of the stingrays varied significantly depending on stocking density. Those stocked at 4 kg/acre grew much larger than those at higher densities, showing that higher stocking density resulted in smaller individual sizes.
Economically, the most profitable stocking density was between 4–8 kg/acre, yielding 370–395 yuan per mu. In contrast, the 15 kg/acre density yielded only 113–130 yuan, due to lower market value for smaller stingrays.
In conclusion, raising stingrays in existing ponds is a viable and effective strategy. It does not interfere with the production of other fish species, requires no additional investment, and maximizes the use of available resources. Based on market demand, the optimal stocking density for stingrays is recommended to be between 4–8 kg/acre. This approach not only improves economic returns but also enhances the overall productivity of the aquaculture system.
Due to the irregular characteristics of the pelvic structure, the choice of internal fixation is diverse.
For patients separated symphysis pubis, a 2 or 4 holes, 4.5 or 3.5mm diameter dynamic compression plate or reconstruction plate can be used and fixed with full-thread cancellous bone screws.Another method of fixation is lag screw fixation. In patients with new sacroiliac joint dislocation with a forward approach,firm fixation can be achieved by using 2holes 3.5mm dynamic compression plates through the front of the sacroiliac joint. The posterior approach can also be used to insert 6.5mm lag screws into the sacral wings or hollow cancellous bone screws with interosseous compression for firm internal fixation. If available, the fracture may be fixed with 3.5mm or 4.5mm pelvic reconstruction plates and appropriate full-thread cancellous bone screws.