Herring pond pollution-free breeding techniques
The herring, also known as barley, snail, black clam, and green clam, is one of China's four major fish species, belonging to the subfamily Kookaburra. This fish has a cylindrical body with flat sides on the tail and a rounded belly. Its upper body and sides are dark, while its underbelly is milky white, and all its fins are grayish-black. As a benthic carnivore, juvenile herring primarily feed on zooplankton, chironomid larvae, and nauplii, while adult herring consume snails, clams, small fish, shrimp, and aquatic insects. In aquaculture settings, they can be fed various compound feeds.
Herring is known for its large size, thick flesh, high fat content, and delicious taste. It has fewer intermuscular bones and is rich in nutrients, containing 19.5 grams of protein and 5.2 grams of fat per 100 grams of meat, along with significant amounts of vitamins and zinc. It is considered the top grade among freshwater fish, offering superior meat quality and high economic value. Greenfish farming has promising prospects due to its pollution-free nature.
**Breeding Environment Requirements**
The aquaculture environment includes atmospheric conditions, water quality, and fish habitat. The environment must meet national standards such as "Environmental Requirements for the Production Environment of Agricultural Products for Safety and Quality of Harmless Aquatic Products" (GB/T184074-2001), "Fisheries Water Quality Standards" (GB/T11607-89), and "Water Quality of Non-Hazardous Food Freshwater Aquaculture Water" (NY5051-2001).
1. **Water Selection**
Herring farming should occur in areas with good ecological conditions, sufficient water sources, and no direct pollution from industrial waste, agriculture, or urban life. No harmful pollutants should exist within the pond or upstream.
2. **Removing Excess Sludge**
Pond sludge consists of organic matter, food remnants, and feces. While some sludge provides nutrients, excessive buildup can release harmful substances like hydrogen sulfide and methane. Every one or two years, excess sludge should be removed by draining the pond and excavating it to maintain a depth of about 20 cm. Exposing the pond bottom to freezing helps eliminate pests and pathogens.
3. **Pond Disinfection**
To improve the environment and prevent disease, ponds should be disinfected using agents like quicklime (200–250 mg/L), bleaching powder (1.0–1.5 mg/L), sodium dichloroisocyanurate (0.3–0.6 mg/L), or trichloroisocyanuric acid (0.2–0.5 mg/L).
4. **Water Quality Management**
Maintaining good water quality is essential for herring growth. The water should have plenty of plankton, adequate dissolved oxygen (>4 mg/L), and a pH between 7 and 8.5. Transparency should be between 25 cm and 40 cm, ensuring a clean, nutrient-rich environment.
**Seed Cultivation**
Producing herring seedlings must follow the Fisheries Law of China and the Quality Standard for Herring Fish Seeds (GB9956–88). Broodstock should come from certified farms, and seed quality must be inspected by qualified professionals.
1. **Selecting Seedlings**
Healthy seedlings are bright, active, and show strong feeding behavior. Poor-quality seedlings may appear sluggish or have physical abnormalities.
2. **Cultivating Seedlings**
Seedling development is divided into two stages: fry and fingerlings. Fry are raised in small ponds with soy milk as initial feed, gradually transitioning to more complex diets. Fingerlings are moved to larger ponds and fed bean cake, snails, and other foods based on their size.
**Adult Fish Breeding**
Ponds should have sufficient water depth (1.5–2.5 m) and area (3,335–6,667 m²). Before stocking, excess sludge is removed, and lime is used for disinfection. Aerator systems and feeding equipment are necessary for efficient management.
**Stocking Fish Species**
Fish should be stocked after disinfectants have dissipated to avoid contamination. Stocking is best done in early spring when water temperatures are low. Each pond should have an appropriate mix of herring, carp, and other compatible species.
**Feeding Management**
Feed must meet safety and nutritional standards. Feeding schedules vary by season, with daily rates ranging from 1.5% to 6.5% of fish weight. Feeding is done multiple times a day, with careful monitoring to ensure optimal intake.
**Disease Prevention and Treatment**
Fish drugs must comply with national guidelines. Preventive measures include regular disinfection and the use of safe chemicals. If diseases occur, prompt diagnosis and treatment are crucial to prevent losses. Common diseases include parasitic infections, bacterial gill disease, and viral hemorrhagic disease.
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