Spring Reservoir Fish Stocking Technique

Reservoirs offer a cost-effective and efficient approach to fish farming, typically without the need for artificial feeding or fertilization. Fish in these environments rely primarily on naturally occurring aquatic organisms as their food source. Therefore, when planning fish stocking in reservoirs, it's essential to consider the types and quantities of available natural bait to ensure that the selected fish species are well-suited to the environment. 1. **Stocking Fish Species** The abundance of plankton in reservoirs makes them ideal for filter-feeding fish such as silver carp and bighead carp, which grow rapidly and reach large sizes. These species are commonly chosen as the main stock due to their wide availability and high growth rates. To make the most of other food sources, it’s also possible to introduce omnivorous and herbivorous species like grass carp, common carp, and tilapia. However, these should be stocked in moderation and not dominate the population, as they may disrupt the ecological balance. 2. **Stocking Size and Quality** High-quality fingerlings with good physical condition are crucial for achieving high yields. For example, common carp and crucian carp should be around 11.55–13.22 cm in length, while bighead carp should measure 13.2–14.85 cm. The size can vary depending on local conditions, reservoir size, and the level of predation by carnivorous fish. In smaller reservoirs with less predation, smaller fish can be used, but larger sizes are generally preferred in more productive environments. Healthy fingerlings improve survival rates and overall productivity. 3. **Stocking Proportions** To optimize the use of natural food resources, the proportion of different fish species must be carefully managed. Typically, bighead carp should make up 60–70% of the total stock, while silver carp account for 30–40%. Other species such as grass carp and omnivorous fish can comprise 10–30% of the total. The exact numbers depend on the availability of natural bait and the existing fish populations that reproduce naturally in the reservoir. 4. **Stocking Density** Stocking density should be adjusted based on the amount of natural bait available. A general guideline is to maintain a dynamic balance between the fish population and the food supply. For example, eutrophic reservoirs can support 110–160 fish per 667 square meters, mesotrophic reservoirs 80–110 fish, and oligotrophic reservoirs 50–80 fish. Adjustments should also consider the growth rate and annual production targets of the fish species. 5. **Stocking Time and Location** The best time to stock fish is in early spring when water temperatures range from 6–10°C. During this period, predatory fish are less active, reducing stress on the newly stocked fish. Stocking locations should be in sheltered, sunny areas near the upper parts of the reservoir where natural food is abundant. In larger reservoirs, multiple stocking points can be used to distribute fish evenly. 6. **Stocking Precautions** Stocking should be done on a sunny day to reduce stress on the fish. When releasing the fish into the water, do so slowly to allow them to acclimate gradually. If possible, treat the fish with disinfectants before stocking. Soaking them in a salt solution (25–40 g/L) for 5–10 minutes can help prevent diseases and promote better health after release.

Bacillus Mucilaginosus

Bacillus Mucilaginosus

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