CATDOLL : CATDOLL: Can grouper be farmed in freshwater?

1. Can grouper be farmed in freshwater?

There are many types of grouper, some of which can be farmed in freshwater, such as the freshwater grouper. Freshwater grouper is native to Nicaragua or Tamarack in Central America. It was introduced to Taiwan in 1988 and is a common freshwater farmed species in southern Taiwan. In 1996, Guangdong and Jiangxi breeding units introduced it from Taiwan; in 1999, it was introduced to the Jinan Freshwater Aquaculture Science Research Institute.

2. How to breed brook grouper?

Breeding technology of stream grouper

Breeding conditions:

1. The water source requires unpolluted stream water, which should be introduced into the pond through channels, with the water entering from one end of the pond and exiting from the other end, with flowing water aquaculture being the main method.

2. The pond size is generally 50-100 square meters, with a water depth of about 1 meter. It is better to put some gravel in the pond so that the grouper can hide. You can also build a shed in a corner of the pond to provide shade to prevent the strong light in the summer from affecting the growth of the grouper.

Farming management:

1. Artificial breeding requires feeding. You can feed high-protein shrimp bait or carp bait, and the protein content should be more than 30%. The amount of feeding depends on the water temperature, the size of the fish, and the weather conditions. Generally speaking, it is best to feed until the fish are 80% full. Feeding method: After the total amount is determined, feed in small amounts and multiple times. Feed slowly and feed after the grouper has finished eating, because grouper does not like to forage for bottom-sinking bait.

2. Daily water management requires clear water, with flowing water as the main feature. In summer, when the light is too strong, shade should be provided in time. When it rains heavily, the water inlet should be closed to prevent muddy water from rushing into the pond and prevent the grouper from escaping.

3. Grouper grows very fast. Generally, it can be put on the market after 6 months of breeding. The individual weight can reach 20 per kilogram. After one year of breeding, the individual weight can reach 10 per kilogram.

Breeding of brook grouper fry

1. Requirements for the cultivation pool

1. Land cultivation

Because freshwater grouper fry have the habit of roaming the walls, the uneven bottom and walls of the earthen pond have a concealing effect, so the area can be slightly larger, but generally not more than 1 mu is appropriate. The water depth is 1.0~1.5 meters, and a few aquatic plants can be planted in the pond (bottom and surface aquatic plants are both OK, such as Vallisneria, water peanuts, water hyacinth, etc.).

2. Cement pool cultivation

The area is 30~80m2, and the water depth is about 1.2m. You can choose a square or round pond, which requires easy drainage and no dead corners.

2. Clean the pool and test the water

Before stocking the fry, drain the pond water, clean and disinfect the pond thoroughly with quicklime, add water 2-3 days after cleaning the pond, and filter the water with a 40-mesh silk screen to prevent enemies from entering the breeding pond. Fry can be stocked 7 days after cleaning the pond and adding water, and test the water before stocking. Before stocking, add 200-250 kg of fermented organic fertilizer per mu to cultivate zooplankton, so that the fry can eat natural bait when they enter the pond.

3. Determine stocking density

The stocking specifications in the same pond should be uniform and of the same size. The stocking density is generally around 100 fish/m2.

4. Bait

1. Fry

The bait for the newly released fry is mainly zooplankton. At this time, fertilizers should be applied according to the water color to cultivate zooplankton such as rotifers and water fleas. Organic or inorganic fertilizers can be applied to keep the transparency of the bird at about 25 cm. If it is more than 1 cm, soybean milk can be added. After 15-20 days of cultivation, the fry will be more than 2 cm.

2. Inch fish

When freshwater grouper fry grows to more than 2 cm, their diet begins to change, and fixed-point feeding should be adopted at this time. They can be fed with fish paste, earthworms, fly maggots, etc. I feed them with dry nematodes, which grow faster. After 3 to 5 days, they can be fed with artificial feed, and then the proportion of artificial compound feed can be gradually increased until all artificial compound feed is used. The daily feeding amount is about 20% of the fish body weight, and feeding is done 3 times a day.

3. Artificial compound feed

The protein content of artificial compound feed is 35%~40%, animal protein should be more than 25%, and plant protein raw materials can be added. The general feed coefficient can reach between 0.8~1.2.

5. Daily Management

1. Timely distribution

Fry have the habit of eating smaller ones and killing each other, so when there is a big difference in growth size, they should be screened in time, graded and raised separately. The size of fry in the same pond should be consistent to avoid affecting the survival rate of fry.

2. Regulate water quality

During the fry cultivation process, the remaining feces and bait due to fertilization and feeding can easily deteriorate the water quality. For this reason, the cement pond should be changed once every 3 to 5 days, and the amount of water changed each time should be enough to drain all the dirt from the bottom of the pond; the land water should be changed 10 to 20 cm per week.

3. Disinfection

After the net is pulled and screened, disinfection must be carried out. The fish body can be soaked in 5% salt water for 15 to 20 minutes, or halogen disinfectant can be sprayed throughout the pond.

4. Patrol the pond

Observe the fish's feeding, activities, water color changes, etc., so as to adjust the amount of feed in time and do a good job in fish disease prevention and control.

After one month of cultivation, the freshwater grouper can be put into the pond for breeding when it grows to about 10 cm. After 5 to 7 months of breeding, it can reach 300 to 400 grams.

The creek grouper is a fish of the order Cypriniformes and family Cyprinidae. Its scientific name is Glossylips. It likes to live in clear, pollution-free creeks with gravel bottoms and fast currents. It likes to forage in shallow waters in spring and summer, and spends the winter in deep pools in autumn and winter. It feeds mainly on benthic algae, and can also eat artificial bait.

3. Can freshwater grouper be raised with carp feed?

Freshwater grouper can be raised with carp feed.

Grouper breeding technology

There are two forms of grouper farming: cage farming and pond farming, among which pond farming is the main one.

Pond farming

1. Pond conditions: The pond can be built by digging in the low-tide or mid-tide area of ​​the reclamation area or by using the existing shrimp breeding pond. The requirements are as follows: (1) The bottom should be sandy or semi-sandy, or hard muddy; (2) The water quality of the surrounding sea area should be clean and transparent; (3) The area of ​​the fish pond should be 5 to 10 mu, and the water depth should be more than 1 meter.

2. Clear the pond and put in artificial fish reefs. After the fish pond has been exposed to the sun and silted, lay some rocks on the bottom of the pond or put in some used tires with holes in them, tile water cylinders, etc. to accommodate the habit of grouper to dig holes.

3. Stocking of fish. The fish species to be farmed must be vigorous, disease-free, black in color, and separated by size. The stocking density must be adapted to local conditions. Generally, the size of the fish species is about 100 grams per fish, and about 0.5 fish can be stocked per square meter.

4. Feeding and management

(1) Feeding. Fresh small fish are the main feed, preferably live bait, and cut into pieces of appropriate size according to the size of the fish. When feeding, feed in a fixed amount, generally accounting for 10 to 15% of the fish's body weight in the early stage and 5 to 10% in the later stage.

The best time to feed is between 5 and 6 in the morning and between 7 and 8 in the evening.

In order to save costs, white shrimp can be put into the fish pond for self-breeding or tilapia summer flower fish can be mixed with it. The leftover bait and feces of grouper can be used as bait for white shrimp and tilapia, which are high-quality baits for grouper, thus achieving a balanced ecology in the fish pond.

(2) Daily management. Groupers are very sensitive to changes in water environment conditions, so daily management should be careful. During breeding, the water temperature should be between 14 and 30°C, the salinity should be between 12 and 35%, the pH value should be between 7.8 and 8.4, and the dissolved oxygen should be above 4 mg/L. The daily change should not be too large, and the daily water exchange volume should generally be 1/3 to 1/4. During the breeding process, if the water exchange conditions are poor and the stocking density is too high, it is easy for the fish to float due to lack of oxygen. Mechanical pumping or oxygenation by aerator should be adopted in time. In addition, ponds should be inspected frequently and safety in production should be paid attention to.

(3) Harvest. Groupers have a poor tolerance to low temperatures, so it is generally best to harvest them before the cold snap arrives. A small number of groupers that do not meet commercial specifications should be overwintered.

Cage culture

1. The selection of breeding sites and the production of cages are similar to those of sea bass cage breeding.

2. Breeding season. The growth period of grouper in Zhejiang sea area is generally from May to November. It takes 14 to 16 months to raise grouper from 50 to 100 grams of fingerlings to 400 to 600 grams of commercial fish. Generally, two breeding cycles are used to arrange production. One is to raise the 100 grams of fingerlings purchased from May to July of the first year to a weight of 150 to 200 grams before winter, and then raise them to the market before winter of the second year after wintering; the other is to release large-sized fingerlings weighing 200 grams from April to May, and raise them to 400 to 600 grams of commercial fish for sale before winter of the same year.

3. Breeding density. Based on many years of production practice and test results, the stocking density of grouper cultured in cages is considered to be 10 kg/m2 per year for cages with a specification of 3×3×3 meters. This stocking density can achieve a higher survival rate, a high total weight gain rate and a high net yield, and a low feed coefficient.

4. Bait and feeding techniques. After being transported and placed in boxes, fish species need 7 to 10 days to adapt to environmental conditions before they can start to eat. They should be trained before formal feeding. The bait is mainly trash fish, and the bait coefficient is generally 7 to 8:1. There are several issues to pay attention to when using compound bait: First, grouper has a strong habit of eating bait. There is a long adaptation and transition process from feeding trash fish to feeding artificial compound bait. Second, the formula of compound bait should be reasonable, and its protein content should not be less than 40%. Third, if the grouper encounters an unpalatable or insufficiently fresh bait, it will vomit, so palatability needs to be considered. Fourth, it needs to be made into soft particles, and its size should be consistent with the caliber of the grouper. Groupers are suspicious and highly selective about bait. Therefore, feeding techniques have a great impact on grouper feeding. Feeding time is from 8 to 11 am, and the feeding amount is about 5 to 10% of the fish's body weight. The feeding method should be slow and wait until the fish have finished eating before feeding. Groupers generally do not eat bait that sinks to the bottom of the cage.

5. Wintering management: From December to April of the following year, the water temperature drops below 15℃, and groupers basically stop eating and swimming, entering the wintering stage.

(1) Selection of wintering sea area and cage structure. Select sea areas with slow current, small wind and waves, and minimum water temperature above 8°C. In order to reduce the impact of tides, wind and waves on wintering fish, some empty cages should be set up around the wintering cages to reduce the impact of water flow and wind and waves on the wintering cages. At the same time, a certain amount of wintering equipment should be set up in the cages, with sacks hung upside down or hard plastic cages and pipes attached.

(2) Stocking density of overwintering fish. Generally, the stocking density of fish weighing 200 g per fish is 350 to 400 per box. During the overwintering period, feeding should be done in warm weather with good winds and less feeding amount, but the bait quality should be better, and live bait should be fed as much as possible.

In addition, places where conditions permit can use indoor heating or land plastic greenhouses to overwinter.