How do eels reproduce?

Yellow eel is a subtropical fish, also known as eel, field eel, long fish, etc. in rural areas. It has a large breeding density in the middle and lower reaches of the Yangtze River in China. It is a very important economic fish. Many people want to get rich by breeding yellow eels . So how do you breed yellow eels? Let’s take a look below.

1. The breeding season of yellow eel

1. The temperature range for the eel's life: The water temperature for the eel's life is 5-30℃, the suitable water temperature is 15-30℃, but 23-28℃ is the most suitable. When the temperature is above 30℃, they eat less; when it is above 32℃, they stop eating and burrow into caves to avoid the heat. When the temperature drops below 15℃, they eat less; when it drops below 10℃, they stop eating; when it drops below 5℃, they burrow into the soil to hibernate.

2. The breeding season of the eel: The breeding season of the eel is from April to August, and the peak breeding period is from May to July.

2. Evolution of male and female eels

Although the eel is dioecious, unlike other creatures, its gender is not constant at birth, but can undergo sexual reversal. That is, eels are female when they are young, and gradually become males after their first spawning and reproduction. Generally, eels less than 24 cm long are female, and eels over 42 cm long are male. When the body length is 25 to 36 cm, female individuals are the majority. At 36 to 38 cm, male and female individuals are almost equal.

Due to the phenomenon of sexual reversal in rice field eels, the number of female eels is small, and the number of eggs carried by female eels is also small, generally only 300 to 800 eggs. This has brought certain difficulties to the demand for large-scale artificial breeding of rice field eel seedlings .

3. The breeding method of eel

1. Yellow eels drill breeding holes: During the breeding season, female and male eels swim together, usually with one female eel and one male eel. Parent eels first dig breeding holes, but breeding holes are different from living holes. Their holes are usually dug on the edge of the water bank. The entrance of the cave is located in a hidden place on the edge of the ridge, and the lower edge of the entrance is submerged in water. The breeding hole is divided into the front hole and the back hole. The front hole is used for laying eggs, while the back hole is longer and slender, but it becomes wider about 10 cm after entering the hole. The vertical distance of the hole is about 5 cm, and the left-right distance is about 10 cm.

2. Yellow eels spit foam to build nests: Before the female eel lays eggs, the male and female parent eels spit foam to build a nest in the front hole, and then the female eel lays eggs on the foam. The purpose of the female eel laying eggs on the foam is to prevent the eggs from sinking to the bottom of the water, so as to avoid insufficient oxygen at the bottom of the water and the inability to naturally hatch into small eels.

3. The male eel fertilizes the eggs: The eel is different from mammals. Mammals are fertilized internally, while the eel is fertilized externally. When the female eel lays eggs on the foam, the male eel immediately discharges semen on the eggs, allowing the eggs to be fertilized and develop on the foam. From June to August, when the water temperature is around 30℃, small eels can usually hatch in 5 to 8 days. However, if the temperature is not suitable, it may take up to 9 to 11 days for the small eels to hatch naturally.

The female eel swims away after laying eggs, but the male eel has the habit of protecting the eggs and will guard them in or around the cave. It will not leave until the baby eels emerge from the membrane, the yolk sac disappears, and they can swim freely and eat.

4. Artificial and natural hatching of eel seedlings

1. Build a pond: Build a breeding pond according to the number of eel seedlings you want to cultivate. The pond should be 70 to 100 cm high. The scale can be large or small, and it can be a cement pool or an earthen pool, as long as it does not leak. However, a smaller eel protection pond should be built in the breeding pond, with more round or rectangular holes left on the pond wall and wire mesh used to separate the holes from the breeding pond. This allows the young eels to swim through the narrow gaps in the wire mesh of the protection pool to the breeding pool, while the parent eels cannot swim from the breeding pool to the young eel protection pool. You can also build earthen ridges around the breeding pond, with a width of 20 cm, and plant some weeds or rice on the ridges. In this way, during the breeding season, the parent eels can move around in the earth ridges and dig holes and spit to build nests. Open a water inlet and outlet in different directions of the pond, and cover the openings with wire mesh to prevent the eels from escaping. After the pool is built, soak it in clean water for 10 to 15 days. After de-alkali, drain the pool water and refill it with new water to a depth of 20 to 30 cm before use. However, some soft and porous objects such as water hyacinth and water lily should be thrown into the breeding pond and the young eel protection pond so that the parent eels can spit foam to build nests and the young eels can live in seclusion.

2. Stocking and feeding broodstock eels: When the water temperature reaches 14℃, the broodstock eels can be placed in the breeding pond, and the ratio of male and female broodstock eels is 2:1 or 3:1. One square meter of breeding pond can hold 3 to 4 male eels and 7 to 8 female eels. After the eels are put into the pond, they should be fed with chopped fresh bait such as earthworms and clam meat.

3. Collect eel eggs: When you see the female eel laying eggs, you should pay attention. When there are black spots on the eggs in the eel nest, you should scoop them up with a ladle and gently pour them among the water hyacinths and other items in the young eel protection pond to allow them to hatch naturally.

4. Cultivate small eels in separate ponds: Newly hatched eels cannot swim and crawl on the bottom of the water or on objects such as water hyacinths. Generally, you will be able to swim after 5 to 8 days. But the baby eels need to be fed 3 days after they are hatched. Use hard-boiled eggs, no egg whites, just the yolks. Wrap the egg yolk in gauze, put it into water and rub it gently. The egg yolk will flow out from the gaps in the gauze, and the small eels can eat the egg yolk water. In the wild, small eels eat bacteria and small plankton in the water. Feed the eels with cooked egg yolks for a few days, and when they grow a little bigger, scoop them up with a net basket made of fine gauze and put them in another pond for breeding. You can feed them with fresh bait such as chopped or pulped earthworms. When the water temperature is between 20 and 28 degrees Celsius, feed them once at 8 to 9 in the morning and once at 2 to 3 in the afternoon. When the water temperature is below 20℃ or above 28℃, feed once a day between 8 and 9 am. After half a year of breeding, eels weighing 10 to 15 grams can be cultivated. When the temperature drops in late November, they will overwinter and can be placed in breeding ponds as seedlings to be raised as commercial eels the following year.

That’s it