Techniques for raising bamboo shoots

Biological characteristics

1. Location classification and structure form

Seabass is also called milk shoots, whose name is English milkfish.

Bamboo shoots are long-stemmed and flattened, with large, medium head, muzzle and round mouth, thick viscous fat film, covering eyeglasses. Nostrils away from each other, small mouth in front, no teeth, no beard. Slightly rough upper jaw. Moderately broad clefts. The hidden membrane carries apart and separates the brisket, the comb carries many, small.

The fish have a rounded wave, difficult to shed, micro-root and anal anus have sheath scales, micro-chest and abdomen with axillary scales, caudal có fin base with 2 long tail scales, fluttering on the developed side. Fish have 1 dorsal fin, low pectoral fins, small pelvic fins, wide caudal fin divided into 2 deep lobes. The back is greenish, measurable and the abdomen is white, the dorsal fin edge of the anal fin and the caudal fin are black, the pectoral and pelvic fins are black at the base. The length of the fish body does not include the tail 3.5 times the height of the body.

2. Distribution characteristics

Seabass is also called milk shoots, whose name is English milkfish.(Photo: stir.ac.uk)

Bamboo shoots are wide-ranging fish species, distributed throughout tropical, tropical and subtropical waters, from the Indian Ocean to the Pacific Ocean. In our country, fish are distributed in the north of the Gulf of Tonkin and the central waters (Khanh Hoa to Thuan Hai) fish grow fast at the temperature of 28-30 ^o C, the temperature is below 15 ^o C, the fish must be wintered.

The fish shoots are very salted, the fish mature and live offshore, the hatched larvae will migrate to the shore, and grow in the lagoon, brackish water mouths or can go deep into freshwater lakes and rivers, fish can resistant to salinity up to 158% ^o , however, over 45% ^o fish will grow slowly, the best salinity for growth is 27- 28% ^o .

3. Nutritional characteristics and growth

In nature, bamboo shoots are predominantly food-based. So the fish also has a gill structure with lots of gills that filter and concentrate the food. However, fry are very unlikely to eat plant plankton, most of which are organic residue humus and water or aquifer deposits (Banno, 1980). Fish have a habit of eating during the day and peak at 7 and 13 hours (Banno, 1980). In the laboratory, fry do not eat at night, but gradually eat at night when they become breeding fish. However, large fish mainly eat during the day, fish start to eat outside from the third day after hatching, when the yolk is exhausted and stage 4-7 days old is a critical period for larvae.

After 3 weeks of age, bamboofish have the characteristics of lab-lab types including cyanobacteria, green algae, algae, crustaceans, insect larvae, earthworms and other substances, mainly: Spirulina, Microcoleus, Anthrospira, Lynbia, Anabaena, Oscillatoria, Nitzschia, Navicula, Amphiprora. Lumut which is mainly greenish filament such as Chaetomorpha, Cladophora, Enteromorpha is also fish food during the big fish phase, but not good for nutrition like lab-lab.

Oscillatoria - a food for bamboofish after 3 weeks of age (Photo: stcsc.edu)

In addition, in fish culture conditions, fish can also adapt and use good artificial food.

Bamboo shoots are medium sized, normally exploited sizes 2- 3 kg, maximum size can be seen 13 kg, fish have a fast growth rate, in natural conditions, 10-14 days after Fish hatches reach 2.5 to 3 cm, when there are many lab-lab fish can reach 0.3- 0.4 kg after 4 months of culture.

4. Reproduction characteristics

Depending on the culture area with different natural conditions, the maturity age of bamboo shoots is also different. Common females mature at 5-6 years of age, males are 4 years old. The size of males at maturity is about 0.9m, females are about 1m, weight is 2-3kg. Under experimental conditions, fish cultured in rafts outside the sea will mature sooner than fish reared in ponds or tanks. As a child, it is difficult to distinguish males and females. When mature can distinguish based on the urinary and anal anus: the female has 3 holes, the male has 2 holes.

Breeding season of fish starts from about 4-5 months. The breeding season can be long and can be laid many times a year. In the breeding season, fish migrate to the sea to pair and lay eggs. The spawning grounds of fish are coral reefs, 20-40m deep, 20 nautical miles offshore. Spawning grounds have stable temperature and salinity at 28oC and 34% o. Fish often migrate to reproduce on the early moon periods, during intense water. Fish spawning at night. Before calving, they paired with the ratio of 1 female and 2 male. The continuous stimulation of two male fish makes the female spawning.

Techniques for raising bamboo shoots

1. Breeding fish seed in earthen ponds

Depending on the nursery conditions, the size of nursery ponds may change. However, the nursery system usually has a nursery pond of 4-10%, a 6% pond, and the rest is a meat pond. In order to provide shelter for fish and convenient for harvesting, farming ponds need to design ditches that cover 2-5m wide, 0.75m deep.

Before nursing, pond preparation is very important to decide the survival and productivity. In pond preparation, the important issue is to create lab-lab, lum and plankton. The steps are as follows:

a. Create lab-lab

Spread manure on pond bottom, dress with a dose of 500-2,000kg / ha depending on old or new ponds. Add 5cm of water, then dry. Add water to 7.5-10 cm. Apply 16-20-0 fertilizer with 100kg / ha or 18-46-0 with 50kg / ha. Every day add 5cm of water, then fill to the desired level like 20-30cm for nursery pond, 30-40cm for pond transfer, 40-50cm for meat pond.

To maintain the continuous development of lab-lab in lagoon ponds, after every 7-10 days, apply 15kg of manure (16-20-0) / ha. 20 days before harvest, fertilizer should be stopped. Hard pond bottom and saltwater 25-32% ^o are good conditions to create lab-lab.

b. Create adventure creatures

The method of creating water color for plankton is not the same as the method of creating lab-lab due to the requirement of deeper water level and often in the rainy season while creating lab-lab in the dry season. Steps like (i) draining the water, then adding it within 24 hours; (ii) adding water to a depth of 60cm; (iii) inorganic fertilizer with a volume of 22kg (18-46-0) / ha; 50kg (16-20-0) / ha; or 25kg (16-20-0) with 25kg (0-20-0) / ha; (iv) after fertilizing for 1 week, it is the same; and (v) apply the above dose each week to maintain a 20-30cm level. Stop fertilizing 2 weeks before harvest.

After preparing the pond, start stocking. Appropriate density for meat production is 1,000-3,000 heads / ha. For nursery ponds, the density is 30-50 individuals / m ² . They are similar to other fish and shrimp species. In addition, it is possible to combine bamboo shoots with shrimp in shrimp ponds with a density of 5,000-1,000 shrimp / ha and 1,000-3,000 bamboo shoots / ha or 1,000 sea crabs and 2,000 fish shoots / ha.

c. Care and management

Managing water quality in the right conditions is crucial to the success of farming. The salt concentration may increase due to low water level and when salinity above 60% o will shock the fish. Therefore, it is necessary to proactively supply water promptly.

In prolonged rainy or cool days, lab-lab can die and lead to lack of oxygen, so there should be remedies when necessary such as water exchange, aeration .

In addition to lab-lab food, in the process of nursing also need to add rice bran, wheat flour, with the rate of 4-10% weight of farmed fish. Feed twice a day in the morning and afternoon. Often supplementary feeding is to fatten fish before harvesting.

When mixing with crabs, carefully barrier to avoid loss.

2. Breeding fish in cages

Cage culture is successful for many centuries in many places and has been promising many prospects.

Like other cage culture methods, selecting the appropriate location is an important starting step and it is necessary to ensure less turbulence, moderate flow of water, covering the floating garbage, the bottom of the clay is meaty and deep most 1.5m.

The fence is fenced with frames, bamboo poles and many mesh layers with appropriate eye sizes. The nursery area is about 10% of the total nursery area.

The stocking density of fingerlings is about 20,000-30,000 individuals / ha with appropriate fish sizes of 6-7 cm. After 2 months of nursing, the fish reached 12.5 cm, then moved to the meat farm. In the nursery phase, supplement rice bran twice a day with a 5% ratio of fish body. During feeding, it is not necessary to feed fish unless in cold months or two weeks before harvesting to fatten fish.

After eight months to a year, the fish can reach 500-800g and can be harvested. The harvesting method can be fin or net.