The main technical measures for fish farming in reservoirs include several key steps to ensure efficient and sustainable aquaculture. First, it is essential to install a fish barrier system at all inlet and outlet points of the reservoir before stocking. This prevents fish from escaping and ensures better control over the population. There are three common types of fish barriers: net-based systems, electric barriers, and bamboo or wooden fences. Among these, the net barrier is widely used due to its effectiveness, low cost, and ease of installation. The net length and height are usually increased by 10-15% compared to the actual width and depth of the area being blocked. The mesh size is determined based on the size of the fish being stocked, with a horizontal shrinkage coefficient typically between 0.6 and 0.7. These nets are often installed using pile structures and secured with two anchoring methods.
Electric fish barriers operate on the principle that fish avoid electric currents. When they encounter an electric field, they change direction, effectively preventing them from passing through. Although effective, this method requires careful management to avoid harming non-target species. Bamboo and wooden fences, while easy to construct and inexpensive, are not suitable for areas prone to heavy flooding and are rarely used today.
Second, the selection and stocking of fish species play a crucial role in reservoir management. In China, many reservoirs have abundant plankton, making salmon a primary choice. However, other species such as grass carp, silver carp, and omnivorous fish can also be stocked to utilize different food sources. The quality and size of fingerlings are important factors. Small fingerlings may struggle to adapt and grow, leading to lower survival rates. Therefore, it is recommended to use fingerlings of appropriate sizes—typically 11.5–13.2 cm for most species, 13.2–14.8 cm for grass carp, and 6.6–8.3 cm for carp. Fish should be healthy, active, and free from disease.
Stocking density and species mix vary depending on the reservoir’s nutrient levels. Eutrophic reservoirs can support 110–140 fish per acre, with a mix of species like silver carp, bighead carp, and grass carp. In less productive reservoirs, stocking densities are lower. For small reservoirs, fish farming can be either extensive or intensive, depending on management capabilities and available resources. Proper planning ensures optimal growth and productivity while minimizing competition among species.
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