Commercial farming process of flower eel

(Baonghean) - The project "Application of scientific and technological advances to build a model for commercial eel farming in Cua Lo Town" chaired by Thanh Vinh Consulting and Development Joint Stock Company, headed by MSc. Nguyen Dinh Vinh has been implemented and achieved good results. From those results, we would like to introduce the process of commercial eel farming in Nghe An province.

Harvesting eels. Photo: Archive

1. Design and construction of eel pond

Eels are a species of fish that burrow into caves and rocky crevices and can escape from the pond, especially when it rains heavily. Therefore, ponds and tanks for raising eels must be high and have fish nets; there must be circulating water in the pond and tanks, and materials to create hiding places for the fish. The pond area can be from 500 - 2,000m²; the pond bottom slopes towards the drain; the average pond water level is from 1.2 - 2.0m. The pond has a bank higher than the highest water level by 60cm or more, the upper part of the pond bank is from 40 - 60cm with a net fence to prevent fish from escaping from the pond, the pond bottom is sand or muddy sand, the bank and bottom of the pond do not seep or leak, and it is convenient to drain and get water, close to the power source. The mud at the bottom of the pond is from 15 - 20cm, the minimum height of the pond bank is 1.5m.

2. Techniques for selecting, raising and domesticating eel fry

- The main source of eel seeds is caught from the wild, the main current fishing methods are: electric shock, fishing line, net, net. Therefore, the selection of seeds is very important, it is necessary to avoid types of seeds caught by electric shock, fishing line (farmed fish have high loss rate, slow growth). The selection criteria must be healthy eels, no scratches, no deformities, fast swimming, bright color, no disease.

- Because wild-caught flower eel fry are often of uneven size and not used to living conditions in captivity, there must be a process of domestication and seed classification before being released into the pond.

- Usually, when caught in the wild, flower eel fry often stop eating for 15-30 days before eating again. Therefore, newly caught flower eel fry should not be released into the pond immediately but must be raised in a tank to control the loss rate, as well as to acclimatize the fish to the artificial farming environment. During this time, it is necessary to manage the water environment well, increase aeration, avoid collisions with fish to reduce scratches, keep quiet, so that the fish can quickly recover their health and get used to the captive environment. Before domesticating the fish, it is necessary to bathe the fish in 0.3-0.5% light salt water for 10-15 minutes.

- Stocking density: From 40-80 fish/m² tank, depending on fish size.

- The food for flower eels in this stage is earthworms and miscellaneous fish. The daily food ration is 5-10% of body weight and the amount of food is adjusted according to the fish's appetite. Vitamin C can be added to the food during this stage.

- After the flower eel has been domesticated and become familiar with captivity conditions, and at the same time meets the set standards, it is released according to technical procedures.

3. Commercial farming techniques for flower eel

*Pond:

- The pond has an area of ​​500 - 1,000m², has been renovated according to the technical process of preparing the pond, especially the water environment conditions ensure the requirements are suitable for the growth and development of flower eel in the commercial farming stage.

* Seed release:

- After the eel fry have been domesticated and become accustomed to the captive environment, especially getting used to using trash fish as food, they are released according to technical requirements.

- Stocking density should be moderate, seed size 50-100g/fish, raised in earthen ponds with density 1-2 fish/m².

* Management care:

- About food: Food for flower eels is fresh trash fish that can be ground or left whole depending on the size of the fish. The food portion is 3-10% of body weight and adjusted according to the development stage and prey-catching activity of the fish. Food is put in a high-sided pot to avoid spilling food, fed twice a day at 8-9am and 4-5pm. Earthworms can be added in the early stages.

- Regarding water quality management: Always maintain stable environmental factors of the pond water, when the water color is pale, you can add the appropriate amount of fertilizer and fertilize in cool weather. Regularly change the water to ensure clean water, and at the same time create a flow in the pond. In the pond, the tank is arranged with shelter materials for fish, the materials are HDPE plastic pipes, old motorbike tires.

In general, the technique of commercial eel farming is similar to many other fish species. The most important thing is the farming structure and pond management when the weather changes to avoid the phenomenon of fish escaping or hiding out.

* Product harvesting and preservation techniques:

- Harvesting: After 15-20 months of raising, when the fish reach a commercial weight of over 1kg/fish, they are harvested. Commercial eels are only valuable when alive, so the harvesting technique must be correct and quick to avoid scratches that cause loss of fish; preparing adequate fish-keeping tools is also very important. Both harvesting methods can be applied: partial harvesting and total harvesting.

+ Harvesting: The larger the size of commercial eels, the higher the value, so during the farming process, the larger ones should be harvested first and the smaller ones should be kept for further farming. The main method of harvesting is to place traps at night and collect the fish in the traps the next morning.

+ Harvesting all: Harvest all at the end of the farming season. Stop feeding the fish 1-2 days before harvesting. Harvest with a hook about 2-3 nights in advance. Drain the water, use a drag net and a net to catch the fish, do not catch them by hand.

- Preserve

+ Prepare a fish tank with clean water and strong aeration.

+ After harvesting, fish must be handled gently to avoid scratching the fish and put into fish holding tanks.

+ During storage, regularly monitor and check the fish to ensure the best storage conditions.

Nguyen Dinh Vinh