What Do Sea Bass Eat? Analysis of Farming Techniques and Market Price Trends
Sea bass has very high nutritional value and is also a highly valuable economic fish. It is distributed along the entire coast of China, prefers to inhabit estuaries, and can also swim upstream into freshwater river areas. So what does it eat? How is it farmed? What are the techniques? And what about the market price trends? According to data on the suborder Percoidei, sea bass is primarily a carnivorous fish with strong predatory instincts and a large food intake. Adult fish often forage alone and prefer to prey on small fish and shrimp. The types of food vary with the size of the fish. Fry within one month of hatching mainly feed on rotifers and small crustaceans. When the total length reaches 5—6 cm, they consume large amounts of aquatic insects and fry. When the total length exceeds 10 cm, they often feed mainly on other small fish. When food is insufficient, cannibalism often occurs.
How is sea bass farmed? What are the techniques?
Sea bass mostly lives at the entrance of coastal rivers and belongs to a type of brackish water fish. This fish is quite large, with the largest reaching over 20 kg. This fish has a very high fecundity; some broodstock can carry over 100 million eggs.
Sea bass lives in shallow sea estuaries and tolerates a wide range of salinity. The seedlings hatch in seawater with a salinity of around 22‰, then swim upstream to live in estuaries where saltwater and freshwater meet, and can enter freshwater areas to forage and grow, but adult fish mostly inhabit brackish water. Sea bass is a fierce carnivorous fish with a large food intake; a single feeding can reach 5%-12% of body weight. Predation intensity is strongest in spring and summer. Fry feed on copepods and mysid shrimp, and after reaching a body length of 10 cm they prey on small fish and shrimp. Sea bass grows relatively fast, with the breeding season generally from November to January of the following year. Fry grow to a body length of 25 cm and a weight of 0?5 jin by the end of the year, and a 6-year-old fish reaches a body length of 0?8 m, with the largest individual reaching 1 m in length and 15-20 kg in weight. Artificially farmed sea bass grow faster, usually reaching over one jin after 280 days of farming. Sea bass can forage and grow normally at water temperatures above 14°C and can overwinter naturally in this region.
Sea bass can grow in freshwater, but according to its natural habits, it is better to choose brackish water areas reached by sea tides, with fish at river mouths and reclaimed areas being optimal. The water salinity can be below 5‰; in waters with excessive salinity, the growth rate actually becomes slower.
Farming techniques:
1. Pond conditions and preparation work
The pond area should preferably be 3300 sq m to 6600 sq m, with a water depth of over 2 m, abundant water sources, unpolluted water quality, good inlet and drainage facilities, and convenient transportation. Before stocking, the pond needs to be dried, desilted, and the slopes leveled and protected. Apply 750 kg to 1050 kg of quicklime per hectare, maintain the pond water at 10-20 cm, and splash the lime slurry. After 7 days, add water to a depth of 1 m. To maintain good water quality, apply 75 kg/hm2 of diammonium once; after two days, when the pond water turns oily green, stocking can begin.
2. Temporary holding and stocking of fingerlings
Sea bass fry are currently mostly caught at sea. Spring sea-caught fry are about 2.5 cm to 4 cm. After catching and transport, the fish will be injured to varying degrees. To improve the survival rate of farming, intermediate temporary holding can be carried out first. The most convenient method of temporary holding is to set up 40-mesh cages in the farming pond. Hold 2000-3000 fry per cubic meter of water, splash with 1×l0-6-2×l0-6 chloramphenicol for disinfection, and after they feed on fish paste, use furazolidone.
For the first 10 days, feed Artemia nauplii or freshwater and marine cladocerans and copepods, then feed fresh fish paste. When the fingerlings are cultivated to about 10 cm, stock them into the grow-out pond at 1.5 fish/m2.
3. Grow-out management
(1) Feeding
The bait is mainly low-value trash fish, supplemented by artificial compound feed. Sea bass grab food quickly and have a large intake, so feeding at fixed times and in fixed amounts is very important. When feeding, make sure the fish eat their fill without wasting bait. Each feeding should start with a small amount to lure the fish to the surface to grab food, then increase the feeding amount. When the fish sink and stop grabbing food, stop feeding. The number of daily feedings and the feeding amount vary with the season. In the suitable temperature season when sea bass grows quickly, feed 4-5 times a day, with the feeding amount at 10-30% of body weight. In the low-temperature early spring and late autumn, feed 2-3 times a day, at 1-10% of body weight.
(2) Pond patrol inspection
Patrol the pond in the morning and evening to observe and deal with any abnormalities promptly. The contents of pond patrol observation include fish activity, changes in pond water color, smell and transparency, as well as pond escape-prevention facilities and predators.
Appendix: Market price trend analysis
1. Sea bass is a delicious fish and also a highly valuable economic fish. We also eat it in our daily lives. Sea bass farming is also a farming project with important prospects and economic benefits. Sea bass has considerable economic value; its flesh is firm and white, and it is not only highly nutritious but also delicious in taste.
2. Sea bass is divided into white bass and black bass due to differences in body surface coloration. Black bass has indistinct black spots; apart from a grayish-white belly, its back and sides are bronze or dark brown. White bass has a whiter body color with irregular black spots on both sides. The market price of sea bass varies from place to place, and prices also differ by size. Wild sea bass on the market is about 25 yuan per jin, live sea bass is about 20 yuan per jin, and live freshwater sea bass is about 18 yuan per jin. Prices fluctuate every month, and the selling price should be somewhat higher.
3. There is not much sea bass of marketable size in ponds, market demand is large, and fish prices rise relatively quickly. Sea bass farming is still not very widespread, but sea bass has very high nutritional value and also certain dietary therapeutic value. After several years of development, sea bass market prices have trended toward stability, and in recent years prices have not fluctuated greatly. Therefore, if the sea bass industry wants to create more profit, it needs to put effort into farming techniques: scientifically farming sea bass to increase yield while reducing inputs such as feed is the only way to obtain greater profits. Farmers may wish to investigate market trends and conditions more and reasonably adjust their own farming plans to strive for higher farming benefits.